How do I increase the font size and scaling of login screen?

Customization
1

How do I increase the font size and scaling of the login screen?

2

Welcome to the Forum!

You could try the following Command:
sudo cp ~/.config/monitors.xml /var/lib/gdm3/.config/

That Command copies the Settings to the Config folder of GDM (the Login Screen) and with that the Login Screen should take over the Resolution and the Scaling.