57 here, and while I am a bit aghast at the idea of having no hobbies and no interests, well, there she is 😬. At the same time, I am also at the stage of life where many of us have to go through our parents' things, if they themselves didn't do a Swedish Death Clean or, more gently, even a Kondo. And just that process in itself can make you very averse to stuff of any description - morbidly, on my bad days, I think "that's all very nice, but will it have any resale value when I croak?" - and the thought of one thing more is just too much. (SIL and BIL gave us a sort of festive pitcher last year, and while beaming enthusiastically while receiving it, my inner thought was "why the merry fuck do you think I would want such a thing? If I had wanted such a thing, do you think I wouldn't have acquired it in my more than half-century of existence?").
I think you can classify gifts in three categories: things, experiences and gestures. Let me explain.
Things: Now, mid/late 50s, I only want things if they are really exceptional - and no, I don't mean yachts or stunning diamonds, I mean one-of-a-kind, I saw this and it could only fit you, kinds of things. Finding that kind of 'thing' happens most easily with people who have a lot of interests and a lot going on, and that just isn't your MIL. Other things are just things, crap to be getting through. If that's what you're reduced to, stick to consumables - that's why people choose chocolate, candles, bath things (anti-thing as I am, I've still asked for posh bubble bath, and I don't mind the odd scented candle).
Experiences can be tickets to an event you know the person will appreciate, a spa outing, whatever. Even better and more meaningful if you as the gift-giver also participate, but that isn't essential. Personally, I'm all about these. The problem is finding the right time or place (still waiting on an escape room promised me a year ago, but I'll wait!). Unfortunately, your MIL sounds as though any conceivable experience would leave her cold. And some people still hang firmly onto something they can actually touch under the Christmas tree.
Gestures are charity donations in lieu of gifts. Nothing at all is 'exchanged', but you know that something you think is important is getting an extra boost. I now exchange charity donations with one of my sisters. The other sister said that it was too cold and unfeeling, and the whole point of Christmas was the physical nature of exchange: I open the present that shows that you thought about me, and you open the present that shows that I thought about you. While I get, and have accepted, her reasoning, I would also note that she is digitally pretty incapable and so that may contribute to her feeling that it isn't really 'real'. The bonkersdom is that we seem to have accepted that the reasonable level of exchange is a book, but no online booksellers offer wrapping anymore, at least not where we are. So I say: a package will be arriving from X. That's your Christmas present. Put it in festive wrapping, and open it on the day! And she says the same in return. Pretty stupidly transactional, but it's important to her. And ultimately it's important to me, because I get something that she thinks I SHOULD read.
The only reason I went into this boring degree of detail was, maybe it's time to establish with your MIL what level of gift-giving she would be comfortable with - if any! Her wrinkled-nose reaction to all of your previous gifts may be, however involuntary, Christ, another fucking thing we have to use. So maybe the best thing is just to be up front with her. "I get maybe that you don't want more stuff - how can we show our appreciation?" "Are you feeling like gift-giving is just piling stuff upon stuff? Can we come up with ideas about how to change it?"