NOnotthemessiah·Aug 30, 2021
Sounds like neovim-gtk has 2/3 (you can resize splits with the mouse, but you can't move them), but unfortunately, it's infrequently updated, sometimes I experience glitches, and it sometimes fails to build.
https://github.com/daa84/neovim-gtk/
In Nvui: A NeoVim GUI written in C++ and Qt