If you are using car play the work around is to have the screen off and use car play without nav full screen (using the view with tiles basically).

Apple Maps can display directions on the lock screen. It seems to also work with turn-by-turn navigation. Does this count toward the global screen time?

You can specify the apps and domains that screentime tracks. I have set a daily time limit for social media and certain domains like news sites and hn but don‘t include maps, mail or messengers