You can start a different TTY than the install automatically starts. Guix has a ‘guix system init‘ command you can point to a system config and mounted filesystem, much like arch’s system init.
If you use the curses-based installer it auto-generates a system config file for you.
Note that the base configuration is entirely libre kernel so some drivers may not work (like wifi)
In order to get these working out of the box you have to make a boot iso with guix with a non-libre kernel.
The system crafters channel has a guide that details using nonguix (a non-libre kernel channel) in the installation out of the box: https://systemcrafters.net/craft-your-system-with-guix/full-system-install/
Good luck! Feel free to DM me I’d you have any questions!