It’s all a case by case basis and no one knows your cat better than you do. If you think there’s a chance that’s it’s not a behavioral issue then go with your gut.
A vet would have no reason to ask you about that if you didn’t bring it up, so no, I don’t think that’s weird.
Personally I would start with the cheapest options and most likely causes and work my way up from there.
Arthritis would be on the top of my list. More litter boxes with shorter walls is an easy solution along with some reconditioning to get her to use the boxes again.
Straining to pee and bloody urine are classic UTI or bladder stone symptoms, but you never know. A urinalysis isn’t very expensive. If she has a full bladder at the vet then they should be able to express her bladder there.
A blood panel isn’t a bad idea to rule things out. Depends how much you want you spend on one vet visit.
Thank you again!! This is all really helpful.
Do you think I should try the different boxes and also cleaning it even more than we do (we do it pretty regularly but not always daily) before seeing the vet? Or see the vet first then try changes? My thing is we’ve always been bad about the box and used to be worse than we are now yet she never used to have any issues. So that’s part of why I think it could be medical or arthritis or something instead of just behavioral. Cause nothing else has changed really. Unless you think maybe she could possibly be stressed and/or lonely from losing Gator? Cause it did seem to get worse after that or really didn’t even start until after that and she also did seem to get kind of depressed for a while after. Seems less depressed now but she’s also been going outside more.
I haven’t noticed her straining to pee or bloody pee or anything like that thankfully. In fact, I’ve watched her just drop and start peeing on the rug right in front of me!

I’m willing to spend whatever to make sure she’s healthy. I mean, obviously I probably wouldn’t spend like thousands or whatever, but getting a few tests one time just to rule stuff out I will do. Unless the vet doesn’t think it’s necessary. Idk.
My main thing is now I’m like super paranoid she has some horrible illness or something cause she’s never had bloodwork so I really want to rule stuff out. But I also don’t want to stress her out by drawing blood and doing a million tests if it’s not necessary but I’m just like super paranoid now haha
I’m glad it’s not weird they haven’t done it though. I was thinking it was supposed to be done regularly like they do with dogs?