No, n95 and better masks have been proven conclusively to protect against it. If your mask isn't fitted right it wont work obviously and surgical masks are not effective. If you are going to be in a poorly ventilated space with someone for an extended period of time an n99 may be better. But otherwise n95s are very effective.
I'm not familiar with any country that mandated or adequately supplies n95s to their citizens.
There's a the question of whether masks can be effective (even without a study, common sense says they are against a respiratory virus) vs. the question of whether they are effective, given actual use.
There's a good argument that idealized use of masks would have been beneficial, but actual use was likely neutral, or even counter productive (caused more unintended harms than prevented infections).
