Just out of curiosity:
- what iphone model did you use for 2 years? Iphones are know to have longer lifespan than androids. My iphone 5 lasted me almost 5 years before I change it. You need to know not to upgrade your firmware as newer ones will slow down the phone.
- what you dislike about your Oppo androids? Maybe those things that you dislike also exist in pure androids like Pixel series.
- what is your requirement for using a phone? Camera? Design? Performance?