Does Din know that Gideon dies? How does Luke know Vader’s alive in Empire Strikes Back? His ship was shot down in space…
You all keep saying plot hole, it’s not a plot hole.
The difference with ESB is that there was a time skip of 3 years in between ANH and that movie, by which point Luke would have has plenty of time to figure out Vader was alive. Mando doesn’t have any time in season 2 to figure that out offscreen, he’s on a mission the whole time. It is a plot hole.