In this scenario, do you have Francis Mauigoa moving to LG? While I agree that Bell is a uniquely talented prospect and think he has a great chance to contribute this season, I don't see him supplanting either of the incumbent Tackles this year barring injury unless whoever takes over at LG this year struggles mightily and the coaches trust Bell enough to start him at Tackle.
I think it's much more likely that Bell serves as the backup to Rivers this season then takes over LT in 2025 as Rivers is more than likely going to declare for the NFL Draft despite having one more year of eligibility remaining.