I love Zellij but it doesn't play well with Neovim. If you try to use both tools heavily (Neovim splits + stacked Zellij panes), your Neovim layouts will get trashed. And if I have to choose between Neovim or basically anything else, Neovim will win.

Sadly, these issues are low priority for the main dev. Instead they are focusing on things like serving terminal sessions over the web, which is useless to me if I can't use Neovim in it.