First Round Play-off RB Help!

Full PPR league. Maybe the play-offs as number 3 seed. My opponent is projected 134 with:

QB- Newton
RB- Barkley, Michel
WR - Adams, Edelman, Hill
TE - Reed
D/ST - Car
K - Lutz

Right now I am projected 127. My team is:

QB - Rivers
RB - Kamara, Chubb
WR - Sanders, Humphries
Flex - Ware
TE - Gronk
D/ST - Broncos
K - Butker

Bench - Gordon, Tate, Boyd, Ekeler, G. Edwards, Wilson, Chiefs D/ST

I am trying to pick-up Jaylen Samuels and Fairbairn off waivers tonight. Any other thoughts? My biggest concern is who to put in my flex that will give me big upside. Thank you footclan!