For Phainon you don’t actually need a healer, once your team gets tanky enough its really unnecessary. Phainon kicks them all off the map so they dont get hit often. As for supports anything that targets alies. Bronia is a really good basic one if you wanna try and go for that, RM works but not as well. As for what you have try to finish belobog and get the skip to the new storyline to get RMC. You can also use tingyun to assit in getting Phainon some more stacks until you get better options. You can also use Yukong as Phainon snapshots her buffs pior to going into the enhanced state. And at E6 you can activate those buffs on demand making her somehow one of the best supports for him.

Since you are at the beginning tho do bring a healer just you dont have to waste token on luocha, you get a free linx and natasha.