Do a test first. Download the Opera installer, launch it, click "options", set "install path" to a folder named "Opera Test" on your desktop, set "install for" to "standalone installation", uncheck "import data from default browser" and install. Once that Opera launches, close it.

Then, open a command prompt and run this command:

"%userprofile%\desktop\Opera Test\launcher.exe" --enable-features=PasswordImport

Then, test in that Opera, but don't enable Opera Sync, don't enable Opera VPN and don't install any extensions. And, before trying to import from Edge or Chrome, make sure they're closed.

Do things work fine there at least?