Haven't tried gnome-mpv,
just mpv and like it better than vlc
.
It's lighter, highly tweakable, takes a minute to configure using mpv.conf (with all the tips and config files available online) and then you're good to go.
Anyway, should you hate it , adding sudo apt remove -y celluloid && apt install -y vlc
to your post-install script shouldn't be too difficult. Moreover, the whole process shouldn't be a huge waste of time since the 19.10 iso will be downloaded quicker.
Using a GNU/Linux distro is sharing a vision you're free to adapt to your tastes. A luxury Windows users don't really have.