Recently I've actually been wondering how the hell researchers manage their citations for big projects, because a while back I started doing some research on the Cass Review, tripped on my own dick and accidentally ended up with 70-something disorganized citations (that I actually used) that were a pain in the ass to clean up.
I'm definitely checking out those first three software lol
I made good experiences with Zotero. Works well with LaTeX, a browser-plugin allows to add papers directly and you can annotate downloaded PDFs. Only problem I had were the paper-metadata, which often needed some fixing. Also that you cannot host your own server is a slight disadvantage.
+1 for Zotero and Biblatex.
You do need the "Better Bibtex"-Plugin though, or at least I highly recommend it.
"Zotfile" allows you to more or less automatically create a filesystem, so as long as you have a way to sync parts of your drive (or access a server) you can have working links to every paper in your library on any machine.
Zotero 7 (the latest main version) broke compatibility with Zotfile, but there are plugins around that are either forks of the version that ran on Zotero 6 or reimplementations of Zotfile’s features.
I personally have been using Zotero Attanger and it’s been working great for me.