back up your own neovim/tmux configs by
cp -r ~/.local/share/nvim ~/.local/share/nvim.bak
cp -r ~/.local/state/nvim ~/.local/share/nvim.bak
cp -r ~/.config/nvim ~/.config/nvim.bak
cp -r ~/.config/tmux ~/.config/tmux.bakand copy the new ones
cp -r dotfiles/* ~/.config