@inlovewithpda OK, don't do that then. That's odd though, because according to https://github.com/Alexays/Waybar Waybar depends on some gtk3 packages.
You can either stop there (you've already given me useful information) or assume that you have some gtk3 installed (for Wayland?), and skip that step - just install the other dependencies.
@semiprime
installing with pip3:
error: externally-managed-environment