I know we can use a main striker. But splashing 70m on a striker just don't seem right...
I would prefer we use this cash to get modric/James/verratti like midfielder. Bacca would score so much more with this kind of players behind him.
Of the mids you named none sound very realistic targets. PSG won't let Verratti go, he'd command huge wages and he probably will want CL. Modric might be possible if he looks for a new challenge, other than that he's probably impossible and too high in the wages department. I am not going to bank on him wanting to move unless he explicitly tells the press so.
James might be possible but it's a long shot too. Morata, Auba and Belotti all seem more achievable.
I'd rather not bank on Bacca. He seems effective from a stats point of view but he is hilariously bad from a build up play perspective. He might hinder us in the type of game Montella wants to play. We need a striker that is more comfortable with playing with the ball and possibly coming deeper to get it. Bacca is not that player.
Since we'll certainly pay such a sum in installments, the overall impact on our budget won't be as punishing as some might think.