Finding a niche is easier said than done, for sure. You should be able to find something which already exists where you can publish your posts, make comments on other people's posts, and take it from there. At worst, you form your own community on Hive blockchain just so you have a place of your own.

Speaking of communities, there are literally 10s of thousands here. If nothing comes to mind, check out this list of communities as shown on PeakD. It's like reading the newspaper at the throne, so just be sure your legs don't fall asleep as you go through that list. If they fall asleep, you may as well keep going through that list until feeling returns to them.