Hi , analysis upon alternative variation in my game seeked.

If instead of 21).Qxg4
opponent plays Qxe5
Some questions:
Why the heck am I winning and how exactly is Qb4 the engine choice ?I mean I can understand his king is a bit weak but so is mine having for instance those isolated triple pawns on my kingside..I also understand his queenside is hard to develop and right now the a1 rook is out of game but surely if I don't generate threats he would solve all his problems.
Also I guess what other practical moves besides Qb4 catch eyes of players (seeking feedback from high rated folks if possible) thanks.

I think the point of Qb4 is just that its very forcing. It attacks the rook but the rook doesn't have many good squares because the e pawn is loose. And if Re2 then the back rank is weak and we have Rf8 or Qf8 with a big attack.

But a more natural looking move is Nf4 and just taking on h3. If c4 then we should be able to play Qb4 with tempo.

Qb4 is obvious engine style move, why? it's because white queen should go away from defending e1 rook anyway, so black may create even more danger by striking e1 rook , because it will be left from defence anyway, and by taking it, we may also give checks and include knigh attack too. so such multiple threats are fit to engine evaluation, that's why it recommends it
if Qxe5 then You may simply attack queen with Rxe3 creating danger for queen and a king pin simuliarosly
so think like engine, and You will catch ideas of his moves

"right now the a1 rook is out of game but surely if I don't generate threats he would solve all his problems"

That's why SF is playing a move like Qb4. It would seem that 21... Rxe3 ought to be okay for you; after all, you look a lot better developed than your opponent after 22 Rxe3 Qxe3+ 23 Qxe3 Nxe3. But then he has 24 b4...guarding against the ...Nc2 idea and harassing your knight (which turns out to not be developed very well on a5). And now he just has to play Nc3 and he's reasonably well developed and ready for anything. Black does have the idea of Rf8/g3 there, but--as long as White doesn't get too greedy (ie, gobbling the a5 knight right away)--he should be able to fend any such notions off. As I just found out by putting the question to SF (it is incidentally a pretty complicated position...so you're not the only one getting a bit bewildered by its vicissitudes).

And one more thing: your kingside is only weak if your opponent can attack it. But--for the moment at least--all he has is his queen over there (which can't do much by itself). And actually, your doubled pawns can act as a shield against many a possible queen check.