Choking hazard. Should I start only feeding her soft foods?

I think there may be two things going on, some dysphagia (swallowing dysfunction) as well as her dementia causing her to lose the ability to slow down.
While you wait for an evaluation from a speech and language pathologist start by assuming she is having difficulty swallowing and offer her more foods finely minced or with a smooth texture. I would also get her a special, pretty TINY plate and limit the amount of food that she has in front of her, don't give her more until she has successfully swallowed what she already has. You may find you need to concentrate on her while your dinner grows cold.
If she hasn't been able to swallow properly she may be gobbling her food because she feels desperately hungry, have you kept track of her weight? Supplements like boost or ensure can help her feel fuller as well as giver her calories needed if that is part of the problem.
And FYI - another facet of swallowing difficulty is choking on fluids, often people need their beverages thickened also.

First I would have your mom have a swallowing evaluation, to make sure that her food is going into her stomach and not her lungs. Aspiration pneumonia can be very deadly, so you want to make sure her food is going where it is supposed to.
My husband had vascular dementia, and developed aspiration pneumonia, which led to sepsis and septic shock, almost killed him, and left him completely bedridden for the last 22 months of his life.
When he first came home I had to puree all his foods, and thicken his drinks with the product Thick It. Eventually I was able to just serve him soft foods, but continued to thicken his drinks.
From a choking stand point, it may be easier to puree her foods as it will be harder for her to try and store foods that are pureed. And you don't have to puree things to real runny consistency, but can leave the food a little thicker(like mashed potatoes,) so it will be easier for her to feed herself without making too big of a mess.
But before you do anything, please have her swallowing checked out. Wishing you the best.

Talk to her doctor to get a swallowing evaluation. The therapist will evaluate your mom's ability to bite, chew and swallow various food textures. He/She can also tell you which thickness/textures of food are safe for her to eat. He/She can give you tips to deal with "pouching", keeping food in cheeks instead of swallowing right away.

This requires medical guidance. Going the wrong way will mean food entering the lungs rather than the stomach and the result will be aspiration pneumonia. You need swallow evals and the guidance of nutritionist to get the correct diet going. She may not be able to tolerate food that is not pureed at this point. Call your doctor and arrange for a "swallow evaluation" which is normally done by OT in a hospital setting.

Although a swallow test might be helpful, would she really be able to participate in this? I had to have this done a number of times, due to a torn esophagus. She may not be able to follow instructions. Certainly a consult with a specialist might provide some insight into observations while she's trying to eat. Given her age (profile says she's 60, but the details say you bought house together when they were in the early 80s, so guessing she's around 90+) and condition, she may not be a good candidate for a swallow test.

The question really should be does she have a swallowing problem (dysphagia, usually causes choking or coughing) or a pocketing problem? I realize they are related, but if she is only pocketing food and can swallow ok, but is just forgetting to chew/swallow before putting more into her mouth, that's a different kettle of fish!

I should think you could do some checking yourself, between meals. Provide her with only a few small items, something she really likes, but not enough to fill her mouth, or maybe even one piece of something at a time and watch for swallowing. Have a drink (straw or sippy cup?) available, so she can wash it down. If she can manage one item and swallow it (encourage her to drink and swallow before providing another piece), then limiting what's on her plate might help. Certainly you'd have to be sure all your plates are far enough away that she can't grab for your food! Avoid dry and hard to chew items, perhaps puree some items, which might go down easier/quicker, but still limit what's on her plate. The use special dishes for pets, which require more effort to get to the food items, which slows down how much they can scarf down - doesn't seem to be any for people, but perhaps one of the pet plates would work, esp for "finger foods" (you did mention she will eat with her hands.)

Limiting what's on her plate during meal times might also help. Although it would restrict what the rest of you eat, perhaps for now eliminate things like corn on the cob or artichokes. Limit the food on her plate to about a mouthful and encourage her to drink and swallow before providing more. It will take more effort on your part, and delay your own eating, but with some patience and guidance, you could limit the pocketing.

I know that my mother, in later stages, was having some difficulty, but mainly with the medication (some of those pills are big and she'd always gagged some when the pills were big!) After her first stroke, swallowing was impacted, as was feeding herself (impacted her dominant side.) She still tried to feed herself, but I found out later that she was refusing or spitting out her medication. They were BP meds, and I asked the pharmacist about opening the capsule and using applesauce, ice cream, anything like that to get it in. She told me the med was time released, so if any were chewed, they'd lose effectiveness, but with applesauce or ice cream, less likely to be chewed and getting some into her was better than none! Due to lockdown, I wasn't able to be there to observe, but it isn't clear they tried this. She did start losing weight, partly from not eating everything and partly due to refusing some. A second stroke finished her off.

There are some charts online which list some sample foods/textures for different levels of dysphagia, such as:

https://www.researchgate.net/figure/Dysphagia-Diet-Levels-and-Appropriate-Foods-to-Eat_tbl3_325908837

This also has suggestions:

https://www.saintlukeskc.org/health-library/dysphagia-diet

I would, myself, want to meet with a dietician and/or speech pathologist to get better recommendations and suggestions for how to handle food pocketing. As I noted, she may not be able to cooperate in the swallow test, but if you can try some methods, diff foods, limit what she has before swallowing, etc, they would have more info to work with.

Invest in a purée machine and make everything as soft and liquid-like as possible.

Your mother needs to have a swallow evaluation. I would discuss it with her primary. She could choke or aspirate. My 98 year old mother has a swallowing delay and now she is on pureed foods and honey consistency liquids. She was coughing before her diagnosis. It has been about two years now. I pureed everything. My mother did very well during the test. I was able to watch the entire procedure. She ate different food textures and it showed on the screen that some food went down her trachea. I was glad I was in the room with her. I take it very seriously and follow all protocol for her safety. Good luck.

Having been through years of dysphagia with my father, I fully support and highly recommend that you ask for a swallowing evaluation, performed by a speech pathologist.

You can also read up on dysphagia; there are several threads here on this topic:

https://www.agingcare.com/search?term=dysphagia

I have a similar problem - sometimes I eat or drink something and it just sits there and won't move. It is horrible, painful and frightening. I suggest a medical intervention and help to see exactly what is happening and how to deal with it. It may help.

In a case like this with a broken brain someone must feed her - she cannot under any circumstances be allowed access to food where she controls what she puts in her mouth. Sad but true - you have no other choice.