Who to start or sit?

So im in a 8 team PPR and we play with two flex postions. Who would you start/sit?

Currently starting:

RB: Bell,Aaron Jones
WR: Julio, Kennen Allen
Flex: Golladay, Fitz

But thinking about possibly putting Sony Micheal in, but not sure if i want to swap him out for Fitz.

Micheal, Cooks, Landry