Finder search links to wrong files, rebuilding Spotlight index doesn't help

I'm on Sequoia, and I've started getting completely unuasble results from Finder search. I do a search and I get what seem to be, based on the file names, the results I'm looking for. But those results link to totally different files.

For example, let's say I search for my home address. The results include a file called Mortgage.pdf, which is documentation from my mortgage. Sounds good. but when I try to open the file, it instead opens a picture of my cats called cats.jpg. If I look at the results more carefully, the path I see is something like /MyDrive/Images/Kitties/Mortgage.pdf. That's not where Mortgage.pdf is located. If, in the search results, I tell it to show the file Mortgage.pdf in its enclosing folder, it opens the folder /MyDrive/Images/Kitties and highlights the file cats.jpg (the same one that opens when I double-click Mortgage.pdf in the search results). So where is the file Mortgage.pdf actually located? Hopefully I remember where I put it, because search won't tell me.

In addition to that, I also get results with just a question mark as a name, and I get file names that don't show a path. If I double-click on one of the ones that don't show a path, I get a message saying that the original of the alias can't be found.

I've tried rebuilding the index multiple times, but I get the same bad results after the index gets rebuilt. I've tried running Disk Utility's First Aid on the disk, but it hasn't found any problems.

Any other suggestions? At this point, search is totally broken, and I'm at a loss for how to fix it.