@Loccaa77 rarely get lag. I have a zte phone, only two gb ram , I do have an additional sd card but the game is installed on the phone not the sd card. If my game starts to lag it's usually after I collected coin for a while or did some kind of activity for a while. I shut my phone down, pull my sd card , wait about 30 seconds , put the card back and the game lag clears itself.
My son has the Google pixel 2 XL which has an 835 processor. He uninstalled the game but told me his worked fine. he has 4gb ram. He tested the game a while ago. We had a few updates since then so not sure how his phone would handle the game now.
This is why Im thinking it's your resolution being higher since your old phone, my current phone and my son's phone are all 1080X 1920