First go to Settings > Add-ons > My Addons
Then Program add-ons > InputStream Helper > Configure
InputStream Helper information will say what version of Widevine you have installed now.
Restore Widevine CDM Library will restore from backup if it exists.
Or Services > SlyGuy Common > Configure > Advanced
Then (Re)install Widevine CDM
Or Video add-ons > HBO Max > Configure > Advanced
Then same as SlyGuy Common.
You should restore or reinstall 4.10.2252.5 for the moment, then reboot and try to play something.