Do they need plot armor when we already know Obi-wan, Leia and Darth Vader survive?
I am (obviously) talking about lazy-ass writing that does not make a good attempt to have key characters make rational decisions and create believable (in the context of the setting) situations for their escape and survival. Creating believable situations involves effort and it is much harder to write and set up and direct, which is why it is increasingly rare in shows like this.
If you do not yet know the context of these kind of "convenient plot armour" discussions by now, considering how prevalent it is in so many lazy and poorly written shows in the last couple of decades, then I am surprised, because it's hardly a new discussion (though no less disappointing).
Personally don't think it was a good idea to have the fight between Obi and Vader - having him hunting him added some decent tension but facing off feels misplaced and like it was done for the wrong reasons (production wise).
If it wasn't for the moments of lazy writing it would be quite good IMO.
Yes it really took what should have been a dramatic and slow-burning confrontation and sucked all of the tension out of it by putting it too early in the show. It should have been a longer build up with more emotion and it just turned into an eye-rolling moment where Vader and all of his stormtroopers cannot apparently chase a slow and lumbering robot carrying a limp body over the next sand dune. Sigh.
Also just what is going on with Vaders chest lights... they are so glaringly bright with so much red and green he looks like a walking traffic light. It's just distractingly bad costume design vs the muted one of the original which I cannot understand why they did not keep.