You can goto the URL opera://settings/passwords and click the kebab menu (3 vertical dots) to the right of "Save Passwords" and export your usernames and passwords to a CSV file. Then, in the Opera on Windows 10, you can import the CSV file via the same menu.
To enable importing passwords though, goto the URL opera://about and take note of the install path. Then, close Opera. Then, open a command prompt and run:
"C:\Program Files\Opera\launcher.exe" --enable-features=PasswordImport(adjust the path to launcher.exe to fit your setup)