I wasn't necessarily trying to criticize, but can you name one successful team making it work at RB with a stable full of essentially undrafted guys?
The closest I can think of is James Robinson (still a 7th) from JAX, but I'm just not buying the complete lack of importance at the position you seem to be selling, especially on this team. If finding any running back anywhere in UDFA is so easy, why haven't we been able to do it?
I know PFF is no gospel, but even for the best OLs in the game, they don't have undrafted rookies back there and thriving.
https://www.pff.com/news/nfl-final-2020-offensive-line-rankings