7...Nc6 not correct, Black wants to trade Qs on e5 not e7.
White will have an extra pawn on e5 with the Queens off, but it is Black's move, and he can immediately attack the pawn which lacks its natural defender, the Nf3. What do you do? Sell out structurally with f4? Guard it from behind with Bf4? Pin and exchange the knight with Bb5? These approaches all have drawbacks. White's even tried returning the pawn with Nc3 Nxe5 Bf4 to try to put Black's Qside under pressure, but I have not seen anything even beginning to resemble a refutation.
I'd very much like to be proven wrong on this, but I don't think one exists. It's unattractive chess, for sure, but White has quite a bit of work to do to get a full point.
For me that's easy, I would play f4. This is a case of a long term advantage for White. White is in no rush to attack. Keep a firm grip on the extra pawn, and slowly progress thru.
This is different than say, a lead in development, which is short term and demands immediate action, which often results in the necessity of a sacrifice.
There surely is no reason to surrender the Bishop pair (i.e. Bb5 Bd7 Bxc6 Bxc6) in an open position with pawns on both sides. Trading pieces whenever possible is great for White. The closer you get to an endgame, the better White gets. Trading Bishop for Knight is probably the only exception to that. But otherwise, any other piece trade is great, so if Black played, say, Bb4+, I would answer with Bd2, not c3.
7...Nc6 not correct, Black wants to trade Qs on e5 not e7.
White will have an extra pawn on e5 with the Queens off, but it is Black's move, and he can immediately attack the pawn which lacks its natural defender, the Nf3. What do you do? Sell out structurally with f4? Guard it from behind with Bf4? Pin and exchange the knight with Bb5? These approaches all have drawbacks. White's even tried returning the pawn with Nc3 Nxe5 Bf4 to try to put Black's Qside under pressure, but I have not seen anything even beginning to resemble a refutation.
I'd very much like to be proven wrong on this, but I don't think one exists. It's unattractive chess, for sure, but White has quite a bit of work to do to get a full point.