I have been back occasionally when searching for some specific thing, and sometimes I checked r/all and my former favorite subs. My overall observation:
Top subs already sucked before the API changes, still looking bad. I don’t have too much comparison, as I wasn’t following them anyway, but I would be surprised if they improved
My former favorite niche subs went downhill, with lower frequency and quality of content. I assume this is due to some mods and powerusers leaving
Overall, reddit is still useful as an occasional information source for checking public opinion/sentiment on specific things, but for me, it’s appeal as a general “time-waster” social media, where I keep scrolling for an hour and leave comments is gone.