Arch Linux pulls the terminfo for wezterm from the ncurses package. This contains an older terminfo that doesn’t contain as many features. For example, neovim’s set title doesn’t work with this terminfo.

An easy way to fix this is to build the terminfo from wezterm’s github repo

curl https://raw.githubusercontent.com/wez/wezterm/main/termwiz/data/wezterm.terminfo | tic -x -