If you're going to make me choose one, I'd take Brieda because I think there is more upside there but I'd be curious about roster size, starting lineups, number of teams, number of keepers per year, etc... That seems like a lot of RBs to have so I'm thinking there may another position that may be a better fit.
Also, depending on the number of keepers, maybe someone else who may have more long term upside would be a better fit for your roster as well.
10 team league, full PPR, return yard scoring as well (1 point for every 10 kickoff/punt return yards) 25 total slots (QB, RB, RB, WR, WR, TE, RB/WR/TE, D/ST, K, 12 bench slots, 4 IR slots). We keep 16 and then have a 5 round rookie/FA draft each year. Here's my current roster:
QB: Brady, Watson, Lamar Jackson
RB: Cook, M. Gordon, A. Collins, L. McCoy, Duke J., C. Thompson, M. Breida, T. Coleman, Jamaal Williams
WR: M. Thomas, A. Cooper, S. Diggs, Marqise Lee, T. Lockett
TE: Kelce, Brate
D/ST: Ravens
K: M. Bryant