HxH already sells more than Academia by a landslide but expecting it to come back without hiatus isn't happening. Academia doesn't even sell close to Haikyuu so keep dreaming of Academia being in the top 3. Academia hasn't surpassed OPM in volume sales too iirc.My Hero Academia has everything ready to be a top 3 except the recognition. Once more people start picking up on it, it'll shoot up high on a lot of lists. Nanatsu no Taizai's not bad and was actually a lot better than I was expecting but I went in with low expectations. If HxH could come back steady it'd be a definite top 3 as well.
As far as popularity goes I'd say the new top 3 are probably OP, AoT and Magi.
No, it's OP, AoT & Haikyuu/Kingdom (I think Haikyuu will beat Kingdom given the third season is airing atm) this year.