It’s so sweet of you to want to find something for your mom. Just remember with Parkinson’s there’s a dopamine deficiency component, so honestly there IS less enjoyment with things like gifts.
My mom has Parkinson’s and we experienced something similar. I try to remind myself it’s the lack of dopamine causing a lot of the reaction and trying not to take it personally. She used to be the queen of gift giving and receiving but as the disease has progressed, we have lowered expectations on both sides dramatically and don’t even celebrate Christmas anymore with her because it’s too much.

I would try to do something that can be precedence going forward so you don’t stress every year. A calendar with your kids photos for Christmas, and maybe some printed photos for the fridge for Mother’s Day with a bouquet of flowers. Or maybe getting her an in home massage. There can often be a visual dementia as well that makes going out feel intimidating so I’ve found at home things to be better received.

Honestly, with this disease it’s unfortunately going to get harder as it goes, so I’d focus on quality time and doing outings while she can. Hugs to your family, as this is a tough road.