I forget why I didn't like Zotero - I am using iLibrarian [0]. It is positioned as a SaaS, but the source is available and you can host it yourself. But I can't speak to how it compares to other software as I am not continually using it. It seems I just like collecting scientific papers rather than actually reading them.... Maybe if I live to 150 will I manage to read them all.
[0] https://i-librarian.net/
And I wholeheartedly second the fact Mendeley is Evil. I got sick of the bugs.