I don’t have this problem on 1.6-s-20221201239247-dev-FP3, and when I was on 1.5-r briefly I didn’t encounter it either.
If occasionally location didn’t seem to work for me in the past, a reboot fixed it for me (on other phones and OSes, too).
You can also try to turn off the phone (no reboot, real shutdown) and turn it on again. I’ve seen real shutdowns make a difference with network hickups of several sorts when reboots didn’t help, so who knows.
GPS only without other means of locating like cell towers or Wi-Fi networks can be slow to get a first location fix (up to quite a few minutes).
For testing be sure to be outside ideally or at least at a window with a healthy chunk of visible sky.
Check that all is ok in Settings - System - microG - Self-Check, especially the location-related permissions in section “Permissions granted”.
Check that Settings - System - microG - Location modules - Mozilla Location Service is enabled (unless you disabled it deliberately).
Check that Settings - Location - Use location is enabled.
Check that Settings - Location - Location Services - Wi-Fi scanning is enabled (unless you disabled it deliberately).
Check that Settings - Location - App location permissions lists the Apps you want to use with location under Allowed (it’s “Allowed only while in use” for me) … else enable Settings - Apps - See all … apps - (the App in question) - Permissions - Location - Allow (probably “Allow only while using the app”).
You can try whether turning on Advanced Privacy, setting the “Manage my location” setting to “Use my real location”, then turning Advanced Privacy off again makes a difference.