you need a reality check my friend, we are in 2022, it is since 2013 that Opera works this way, since they abandoned Presto to use blink/chromium, every browser has deals with search providers to include their engines, that is how browser companies make money and give us for free a complicated piece of software. We can only guess why Opera has chosen this way, but is seems elementary that if you structure your browser this way you will get a better deal - read it: more money - with DDG, G et cetera
nine years ago I totally hated this "novelty" - I complained tons of times on the Opera blog, I arrived to the point of quitting Opera, today I have learned to live with it, it is a matter of habit, every browser comes with his hiccups, Opera has a handful of unique features which make my browsing better, it is a live with it or leave it situation, your choice.