Do you happen to run an antivirus or you had one during the Windows 10 updating process? This to me sounds more like something went bad and it's not really Opera's fault. I mean, I use Opera too and have updated 3 systems from 1803 to 1809. Opera works fine.

I think doing a clean Windows reinstall from USB would be the best solution (the reset feature in Windows tends to leave drivers in latest state which can be a problem). Back in the Win9x days it was annoying because reinstallations took hours. Now you can be done in 1-2 hours doing a clean Win10 install with almost guaranteed success because I see no reason why this should be exclusive only to Opera.