Another thing you can try is to temporarily create a new user account, log into it and installing Opera there just to test if it works to test if the issue is limited to just your user account or not.
This bug is really annoying because it is inconsistent and really hard to reproduce. Sometimes when you type absolutely unrelated to shopping things like "Linkin Park new album" or "python tutorial" the address bar shows Opera Suggestion as the first option in the search bar dropdown and opens completely empty and useless page. The second annoying part is you have to retype the prompt because now it is gone completely and pay attention and pick 'Google Search' instead of 'Opera Suggestions'.
@discobolus In the latest Opera update (v113.0.5230.94), changes to the address bar may show different search results. To fix this, go to Settings > Search engine and set Google as the default. You can also turn off extra suggestions by going to the Advanced section in settings.