Best MP3? Esound. Best photo? Like editing? Canva. Best browser? In my opinion it's Brave. But a lot of people say OperaGX or a tor browser. I don't know what a customization app is so I'm no help there.
Best photos or wallpapers? If you want an unlimited assortment of wallpapers to choose from, 7fon is the absolute best. Has lots of categories and adds new ones on a daily basis. You can add them in a Favorited category if you want. Best part: It's absolutely FREE. Try it out. You'll love itโบ๏ธ
