@BlueWingsPetya You can only do it manually.

Really it seems that's right

@echo off
"C:\Program Files (x86)\Opera\opera.exe"
rd /s /q "C:\Users\Petya\AppData\Local\Opera Software\Opera Stable\Cache\"
echo Opera cache was cleared. If you're fast enough, you can read this line ... :D :P

1st I tried this code, but it doesn't work since opera.exe starts another instance of itself, then quits.
2nd I tried searching for an addon, installed about 10 or so, 1 had such an option to clear items separately one-by-one at exit, but it didn't work.
3rd I installed Opera to Win10 to see wheteher there are differences in options, there's no diff.
4th I installed Vivaldi again, to see if it is capable, it is not. Only Firefox can do that.

Finally, it was nice to see that Opera and Vivaldi works again on Win7.
Few years ago I abandoned both on 30. September 2021 when the certificate problem stopped both from working properly. From then until today I used Firefox only.

Opera was my primary browser for years at the time when it had an integrated email client. Once upon a time (18 years ago) I even purchased it('s premium support for 1 year). Today I saw that Opera went far towards trends dictated by big companies like Microsoft etc., while Firefox didn't. Therefore I will leave my daily work in Firefox, but if anything goes wrong there, 1st place I will try the same in Opera, before doing any research or forum posts.

Thanks, Peter