When esports team change at Fortnite, do they move directly from the respective team to the gaming house?

When esports team change at Fortnite, do they move directly to the gaming house from the respective team?!

No, not necessarily

And why not?

It depends on the agreement maybe some don't want to move?

There's definitely a house where you can go to e.g. Train or live, but most so-called "clans" (or teams) have no permanent residence where the members can go. (Incidentally, whether they move or not depends primarily on their contract)