When Sabine shows up on Peridea and meets Ezra, she's without a ship, and she’s riding a saddled howler. She won’t answer Ezra's questions about how she got there, and she won’t talk about going home. There are new villains chasing them, who Ezra doesn’t know but Sabine does. Then Ahsoka shows up, and he learns that she and Sabine didn’t travel together in her ship because Sabine thought she was dead.
So Ezra must be wondering then...how did Sabine get to Peridea? Right?
Ahsoka leads Ezra and Sabine to the Chimaera and the new hyperspace ring in an effort to stop Thrawn from escaping Peridea. (This means that Ezra now knows that this ring arrived on Peridea in the last day or so, around the same time as Sabine. He's never seen it before! In ten years on this barren, desolate planet!)
They all storm the tower to try to either stop the ship, defeat Thrawn together, or infiltrate it for a ride home, so Ezra surely must know by then that the hyperspace ring can cross galaxies (and therefore that’s how it must have gotten there in the first place). Ezra then leaves aboard the Chimaera.
Do we really think Ezra is completely clueless as to what’s going on? How Sabine got there?! Is he really going to be all “shocked pikachu face” if or when the whole story about the map is revealed to him? He was already suspicious within minutes of reuniting with Sabine, so even though she hasn’t told him anything in particular yet, he has to assume it cost her something. If she had merely stowed away or been a prisoner, as they had done so many times in the old days, then she would have just told him how she’d gotten there with the bad guys and why going home was unlikely.
If Sabine (or Ahsoka) didn't tell Ezra about the map already (off-screen), then I don’t actually think Dave will spend the time to go back and reveal it to Ezra somehow. It would be kind of unnecessary, wouldn't it? What would be the point? Ezra must have already done the math.
The beef with the map was between Ahsoka and Sabine, and they cleared that up already. It no longer matters to Ezra what Sabine did to get to Peridea because she sent him home, and Ezra is already well-aware of the current threat of Thrawn to the galaxy.
