Again, OP (along with her parents) can decide how they want to handle things. OP knew the risks when they made their OP, now it’s up to them to decide how to move forward, if they want to change things up.
I agree no obligation. With that said, some sports and some divisions/conferences behave differently than others. Don’t know OP’s sport, so can’t comment on that. Regardless, it’s out of OP’s control how Coach A might react if they talk with Coach B without telling Coach A and Coach A finds out.
Have a third party, a club or school representative or some other coach, make some calls to school B and see what’s available for a hypothetical athlete looking to change commitments. If your current coach really is a legend then he’ll totally understand what needs to be done. And the coach at B will immediately understand that the legend probably only has one D1 commit at the moment and know who is being discussed.
The larger question is the fit. The money part makes sense. The hesitation due to your club’s expectation of prestige is their problem, so ignore it. The academic thing is a maybe, since you can get a very good education at a thousand schools and chances are both A and B are among them.
But if you just have a general unease with your choice take a moment to discern if it’s with A or just your comfort with how the process has gone so far. Is there something specific about that program at A that’s rankling? Sure, explore talking to to B. But talk to A again too and express concerns with the academic rigor, clarify your fit in their world, let them reassure you. Even if the discomfort remains it’s a good way to signal that you’re restless.