Same issue here with 123 update!
A work around for now is to downgrade to 122 (you can find that here https://get.opera.com/ftp/pub/opera/desktop/122.0.5643.92/). For Windows you want Opera_122.0.5643.92_Setup.exe and just run the exe. After installation immediately close the browser and go to your opera installation folder and rename opera_autoupdate.exe as @KotTHECat suggested.
Waiting for future update that fixes this. Huge F up!