Dotfiles! for indentation issues: :TSUninstall python :TSInstallInfo Also, :UpdateRemotePlugins is very helpful.
Put all the theming files in the $HOME/, or ~/ folder. Create a ~/wallpapers/ directory to put wallpapers. Go to a terminal and run the 't' command, which will switch wallpapers to light or dark mode.
:checkhealth is very useful for seeing any broken plugins.