Do you use Opera Sync? If so, are you encrypting your data with a custom passphrase? Do you user Opera's VPN? Are you blocking 3rd party cookies? Have you cleared all cookies for google.com? Have you tried disabling all your extensions? Are you using Opera's adblocker? If you download the Opera installer, launch it, click "options", set "install path" to a folder on your desktop, set "install for" to "standalone installation", uncheck any checkboxes, you want and install (do not enable sync or anything in it), how does that Opera behave (right now at least)?

Most probably you were using an extension, Opera Chromium never allowed the user to change the position of tab bar.

If your software manager has "additional repositories" you can add Opera so it will update with: deb https://deb.opera.com/opera-stable/ stable non-free #Opera Browser (final releases)

What is Opera's OS? What is the problem?

@concretable Delete metadata folder from unzipped pack. Also remove possible update url from manifest.JSON. Deleting metadata makes sure that Opera uses only your local files.