There are a couple of things possibly at play. Bookmarks are usually saved through your browser and not on a particular site. Are you using the same browser now? Firefox particularly likes to hide my bookmarks just about every time it updates -- the data is still there but I have to typically do a search on how to bring the bar back.
The format here and I think hosting site changed early 2020?? We had to learn some new techniques, especially with posting pictures. If it was available through the site, it was a feature I didn't use and it may be gone now.
I do have bookmarks for threads here in the old format, those bookmarks still work.