Mine is also toothless by now. You are correct, my vet told my they’re using their upper denture / jaw to crush what needs to be crushed and swallow everything else.

I was told to be careful with wet food and meat because this kind of stuff can’t be crushed so it should be “bite sized” to allow her to swallow her food easily. But I don’t know if this is a general thing or if this was related to an incident when my cat nearly suffocated from a piece of sausage she greedily swallowed without chewing… She’s never been the sharpest tool in the shed, but we love her (⁠人⁠ ⁠•͈⁠ᴗ⁠•͈⁠)

That’s no comfort at all…

We once had a rescue like Willow. He decided to live behind a bunch of boxes and only came out when he thought he was alone. Even with the other cats he was like “nah”. Until one day someone dropped a toy made of fake fur and feathers close to his hideout. 180 personality change. He completely lost it and was so focused on this stupid thing that socializing suddenly was no issue at all if he was allowed to bring his toy. Bonus points and cuddles if you engaged in his play. It was fascinating.