I had the Pixel 6a and couldn't install via Google Play because "app won't work" message.
The Pixel 8 installs just fine at first instance. Then I created a user profile and failed to install with "unknown error" after downloading via Google Play.
I then tried on Aurora Store. Failed:
Invalid or corrupted APK
INSTALL_FAILED_VERSION_DOWNGRADE: Downgrade detected: Update version code 124716 is older than current 125314.
I did a manual download with a version code 125314 and it installed fine.
I have no idea what just happened. Did it try to download an older version when a newer version is available?