Feel limited by tmux with niri.

I feel like there are limitations to using tmux with niri in that I can't have more than 3-4 panes because the terminal has to be full screen also changing to a different control scheme, from using my OS keyboard movement, to tmux keyboard movement(which feels 100x worse than niri). Obviously I can open up multiple terminals but there is no sessions there, so is there a tool that has sessions with multiple terminals not panes or windows full terminals?