[Returning player] Why is it much harder in the rank 1's than in the rank 2's?

I returned after maybe 2 years of not playing, i got most british Rank 2 which i mostly play and have very good results in.

But when i tried starting with japanese planes from scratch the enemy players seem much much tougher and so to say experienced than the ones i face in my rank 2 planes.

I know i am still not a decent player but again, as brits Rank 2 i am often the most scored player in the team but when i play from scratch with japan i get absolutely wrecked by 3/4 players i fight.

Does anybody know why it is so? If i were a brand new player i'd given up on the game tbh.