I guess trust the scouting, and if the Fins believe Burrow is the guy then go for it. But it's not like they're one player away from contention, and they could entertain the idea of building up the rest of the roster first with their cache of picks. If they can't protect a young QB or provide him with weapons then what's the point? I think it makes the most sense for them to stay put and take either Tua or Herbert at five if they really like either one and then use their other picks to help out the new guy.
Here's a question - if Burrow makes it clear that he won't play for the Bengals and they just take Chase Young or another non-QB first overall then how far does Burrow drop? Is it possible he falls to five in that event? After the Bengals you have the Redskins, Lions and Giants - all of whom either have an established QB or are invested in a young starter.