Another Kröhnkite user here. I used tiling window managers before (mainly Qtile) and cannot use a desktop without auto tiling anymore.

Kröhnkite: is THE tiling addon for KDE in my experience. There was a period when it was broken and I experimented with other solutions (Polonium worked for a while, but now that thing stopped working lol and Kröhnkite works well again). You just need to setup your keybindings and configure the limited configuration itself. You can also remove the title bars and have colored outline for active window, if that is your thing. But that is not very configurable and is a weak point in my opinion.

Karousel: a scrollable tiling window manager. If that is your thing. It worked fine, I'm just not a fan of this type.

Mouse Tiler: and then there is a new and promising addon script in the works. The main selling point was and is that tiling is done manually and with mouse only. But after lot of request the dev is working on an automatic tiling system, which puts it into my radar. And I hope it will have configurable keyboard shortcuts too. Dev says the auto tiling works already and in the next days it will be updated. Didn't try it out yet, but looks promising to me.