I was checking options in settings and I applied default theme. Now I can't take it off. I checked on internet how to fix it, but apparently you need oppo theme store
Oppo Theme Store update revamps UI & adds new collection - PiunikaWeb
Realme & OPPO Theme Store New Update With New Features [v9.3.0]
The theme on the Oppo phone is in the theme store | Kartu 3d, Kartu lucu, Kartu