The literal only champs that are locked to 5* rarity at max are Quake and Magik, and Magik is eventually going to leave Quake all on her lonesome once she gets her rework and accompanying 7* release via the radiance store.
Just rank up whichever 5*s you need to complete content until your 6* and 7* roster grows enough to replace it.
Thank you. I got Magik maxed & haven’t been blessed with Quake yet. I will rank according to content & preferences.
QUAKE, oh you don't have quake. Well sorry bro...
Quake will take some practice to master. Once you do, however, you'll bypass nodes and scare away defenders. And any thumb war hustlers you come across. Get them popeye thumb muscles from quake n bakin.
Try not to waste any resources on 5* and move to 6* as soon as possible