not it would be not. bernar is unproven
Compared to Di Maria, sure, but Di Maria is almost 30, and for a pacey winger, that is when the decline begins. Compared to Costa? I'm not too sure.
1) Costa was fantastic in Ukraine, but struggled big time in Germany after a good .5 a first season with Pep.
2) Bernardeschi was utilized all over the place, playing effectively for Fiorentina, a good but not great Serie A side. Bernardeschi has been effectively used at left wingback, right wingback, a winger and a trequartista. That is impressive in my eyes.