Personally, I would stick with Geno over Lamar straight up. I feel like Geno has more capability to take advantage of the playmakers on this offense.
I think our offensive personnel with 3 dangerous receivers is the type of passing attack that can take a team far in the postseason, provided defense and running game are working as well. Geno is a quarterback who, when provided protection, has traditionally excelled when provided multiple viable receiving threats dating back to his WVU career.
Lamar, however, has a great regular season floor if he remains healthy. His legs are an incredibly taxing threat to a defense. This opens up the rushing game immensely. He also makes decent use of his tight ends and isn't a *bad* passer by any means - he just isn't a structured passer. You'll live and die by his playmaking ability, so the postseason is a bit of a crapshoot especially if you run into a buzzsaw of a defense.
If I'm saddled with Lamar as my quarterback, I am not mourning by any means. I'm hiring a Shanahan tree offensive coordinator to dial up a rushing attack and hiring Darrell Bevell to coordinate my pass game, as he does very well with these types of quarterbacks.
Geno, though, is much more my style. Pocket navigator, eyes downfield, and has a totally natural stroke. Ball pops out of his hand with velocity and a tight spiral. Same reason why I would've taken Drake Maye #1 over Caleb and Jayden.