Thanks. Alternative suggestions welcome.
By the way, for me, when it comes to scrolling, the most urgent is to find a more elegant way to decouple the list of feeds (on the left) and the list of articles (on the right) to allow scrolling down to the bottom of a long list of feeds without scrolling the articles, and thus without auto-marking them as read

A simple decoupling could be done by just removing sticky-kit, and would leave the feed list at the top, like the behavior of feeds in versions prior to... 1.5, it looks like (#1214)?

Without sticky-kit, individual scrolling of the sidebar and main feeds could be accomplished purely through css. I've tossed together a quick proof-of-concept here: https://github.com/pattems/FreshRSS/tree/Sticky_aside

This isn't a terribly robust solution, however. There's problems with the last feed or two being obscured by nav buttons if they're visible, but with a bit more work it's a viable, if slightly hacky, pure-css solution.

I'm not terribly good with Javascript, but I think I can probably throw together a JS replacement for sticky-kit that will let us have those decoupled feeds, it might just need a little extra polishing by more capable hands after I'm done with it. I'm not making any promises, but I hope to have something together by My Friday evening/Your Saturday morning.