I gave Zellij a shot a few months ago. It really felt too "modal" for me though. I've been a Vim user forever so I'm not exactly modal-averse. But TMUX has always felt more like Operator Pending mode in Vim. Having Zellij feel like full-on Normal mode was frustrating. After I gave up, someone told me they had their Zellij configured just like TMUX, and I should give it another shot with their config. I still haven't gotten around to it.

Zellij has added a "locked" mode (defaults to Ctrl + g) where it acts just like Vim's normal/insert modes. So when to do mux commands you unlock it first.

could you share that config please? as a tmux user i feel like i might run into the same problems, and so a tmux like setup might be a good start.