Inter is very nice, but personally I’ve taken to Iosevka Aile and it’s what I’m using on my own workstation for UI don’t (along with Iosevka Mono for code).

Can you not just change it yourself in Gnome Tweaks? Which font is it they are using?

But the GDM font remains the same

That has to be changed in the GDM theme. Look in /usr/share/gdm/themes . Find the XML greeter file for the theme you are using, make a backup, and edit the font attributes.

Thank you!