It's a complicated question because if you think about absolute talent ceiling, Vlad wins. If he pulled his head out of his ass he SHOULD be able to hit like 2021 Vlad did fairly consistently. That's a guy I want for the next 10 years.
But in real world ceiling...Bo wins.
Bo has a higher ceiling but that's largely due to the position he plays. With even modest improvement on defense... he's a 7 fWAR+ guy at his peak. 150 wrc+ bat with even average SS defense is money in the bank. I dont think he'll ever be elite D, but maybe even slightly above average is well within the realm of possibility.
The downside of Vlad... well... we're seeing it. Tremendously skilled bat to ball tendencies have him swinging at garbage he should swing at and prevents his power from playing up to where it should. 2-3 fWAR floor though simply because when he does contact the ball, the EVs are savage. Usefull player, but not a guy you sign to a 10 year deal hoping you get more ceiling and less floor.
Bo's downside... probably 3.5-5 fWAR. His bat is prone to going into streaks where the babip gods torment him and he'll probably never walk alot. But because of his hit tool and power his offensive floor is right around 120 wRC+. That's probably even low given that his worst season output is the COVID shortened 2020 when he put up... 120. any full season has been 122 and 129. He has a higher floor and a higher chance of playing near his ceiling IMO.
Vlads ceiling right now is more of a dream than a reality. Bo's ceiling is actually kind of in view.