@venomweb99 I even tried "opera://flags" settings by selecting "disable" for every feature that included a word "suggest" or "auto" or "drop" or "address".
Final solution for me has been to move to Vivaldi.
Vivaldi requires a second password for syncing data, which is annoying, but I can live with that. Typing my search words and pressing enter, only to see Opera browser doing something I didn't intend--just because my selection bar was placed on some random option suggested by Opera while I was typing--is unacceptable. Why do I use a computer? Because machines do only what I tell them to do--not Opera.