There is no such thing as top 10 QB money for a franchise QB anymore. You either get paid top 5 or you're not The Guy™ for that franchise. Dak's contract made him the highest paid player, Hurt's contract made him the highest paid player, Love's contract made him the highest paid player, Goff's contract made him the second highest paid player, Kyler's contract made him the second highest paid player, Tua's contract made him the 5th highest paid player. The only alternatives are 36 year old Kirk Cousins becoming the 12th highest paid QB and the team drafting a top 10 pick QB months later, or a journeyman Baker Mayfield on his 4th team in as many years becoming the 15th highest paid QB. Derek Carr might be an interesting example though. When he was in Purdy's position, he was made the highest paid player in the league, but years later he was cut and got his current deal with the Saints that made him the 15th highest paid I think.
So the question is, is Brock closer to 32 year old Carr, 36 year old Cousins and 29 year old Mayfield, or is he closer to Tua, Goff and Love. I think he's closer to the latter group, so he'll probably get a Tua-type contract where he's made the 5th or so highest paid QB.