Download the latest version of Opera GX. That's https://ftp.opera.com/pub/opera_gx/94.0.4606.107/win/ (Opera_GX_94.0.4606.107_Setup_x64.exe) at the moment.

Goto the URL opera://about, take note of the "install" path, and close Opera.

Then, uninstall Opera (don't choose to delete your data when uninstalling).

Then, delete the install folder if it remains.

Then, delete everything in "C:\Windows\temp" and "C:\Users\yourusername\AppData\Local\temp" (skip files Windows won't let you delete). There are Opera installer leftovers there, so clearing these can help.

Then, open the Windows Task Scheduler and make sure there are no Opera tasks in the library.

Then, delete any Opera shortcuts (start menu, desktop, taskbar) that you have.

Then, launch the Opera installer, click "options", uncheck "import data from default browser", adjust all the other install options as you like, and install.

That should clear any installer/updater issues up that you were encountering (if there were any actual issues). Then, you can disable updates again if you want, and even modify Opera's shortcuts again to use --disable-update for extra good measure if you want.

You can then check https://ftp.opera.com/pub/opera_gx/ (by date) and https://forums.opera.com/topic/33033/opera-gx-update-released whenever you want to see if there's a new update. The latter takes a bit longer to get updated, so the former is a more reliable check. You can bookmark those if you want.

Then, whenever you want to update, download the installer, launch it, click "options", make sure the path is right so the installer says "upgrade", review the other options, and install.

After an update, you can go through and make sure all update stuff is disabled again. And, in the install folder, you can delete the older version folder and any old launcher files (if present), and the "old_status" folder if you want, so you can keep the install folder clean.

Regards,
Eleusius.