Some users of Android smartwatches have complained that Google Maps fails to show any information follwing its newest updates. This issue was originally thought to affect Ticwatch devices only, but has also been reported on watches from other OEMs. To date, it appears that uninstalling updates is the only valid fix.
https://www.notebookcheck.net/Google-Maps-reported-to-show-blank-screen-on-some-Wear-OS-watches.419744.0.html