I mean it works for me now, see my comment where I talked about some of the unreasonably extensive configuration I had to do to make it work the way I wanted. At this point I have CLIPBOARD automatically synced to PRIMARY, so I can always copy something and then middle-click and I’ll get it. And I still have nice behavior that Linux generally makes possible (being able to copy and paste out of terminals even if I’m scrolling around on the thing within the terminal while I’m doing it). Now if someone can just teach Ubuntu what xterm-kitty as the terminal setting means, when I have to ssh to an Ubuntu machine, I can finally be happy.