the fact that 1.8 was working tells me that it is possible for a window manager to work well for nvidia

Nope, it's a race condition for which the visible effects can appear or disappear for plenty of reasons. The only fix is explicit sync, which is being worked on for wlroots

Hyprland works great as long as you make sure to get the build with nvidia patches to prevent flickering. It's very similar to i3, although not 1:1 like sway.

Until its drivers are completely open source, Nvidia will continue to cause trouble every once in a while.

Therefore, if you liked Sway, then don't leave it expecting to be a lot better elsewhere.

However, Hyprland's community is pretty big and I can only be positive regarding the pace of its development. Therefore, if anything, Hyprland might be able to offer a solution. But, don't forget what I said earlier*.

i use kde plasma with polonium with zero issues

labwc is working pretty well these days. Screen tearing for games and all.

There are a bunch of environment variables that I set this time though, which may have contributed to a better experience this time.

Hyprland is my favorite tilling manager for Wayland. Its really easy to customize or find dotfiles. I have some if you want them.

If you want something that just works, popos-shell gnome plugin

Does hyprland work for your setup?