Others here have already addressed a lot of the issues I had with this episode, but I just wanna say:
This episode made me feel how I felt watching some classic Doctor Who episodes that were bad, but which I felt I had to get through to get to the good parts. I've never felt like this in the modern era (except perhaps a few bad episodes in Capaldi's first series), but this... The previous Chibnall series were bad, but this just takes the cake.
And can I say? I really don't care for Whittaker's Doctor. I've been watching some clips with the previous modern Doctors, and they all had that magical energy about them, like they were excited about life and wanted to take us on a grand tour of all time and space. Whittaker has nothing of this energy. The writing's largely to blame, but there is something about her performance, too, that lacks a certain depth and quality. I was hoping that, like Capaldi, she would find her footing after a season or two, but her character is actually regressing as we head out into her last appearance.
I like to think that in a few years, when RTD has steered the ship right again, I'll be thinking back to this episode as another one of the dark periods of Who fandom.
This is the first episode for me when the show has lost its shine. I adored the first three episodes and thought episodes 4 and 5 were okay, but man, this one was just terrible.
There are a few reasons I can think of:
The overarching plot has taken a backseat. Episodes 1-4 felt connected by the Mandalorian's quest for redemption through his care for the Child. Episode 4 still felt connected to that overarching goal, but with the last two episodes, we're just watching a "job of the week" conceit that neither moves the characters nor the plot forward. It's basically filler at this point.
Bad Western tropes. While I loved the initial "Western in space" feel of the early episodes, the show was still coming up with its own genre conventions and telling an original story. With episode 6, we're getting a pretty crappy heist gone bad story whose only claim to originality is being set in the Star Wars universe. All the turns were painfully predictable and dictated by the tropes of the genre rather than the characters themselves.
Bad acting. The Twi'leks and the horned guy were just awful. The dialogue was bad, but the way they hammed it up was just painful to watch. Watching the Twi'lek girl hiss at the horned guy felt like watching D&D players hamming it up on game night.
Bad writing. The whole thing was just so unbelievable, from the predictable turns to the way Mando eventually betrays his employer using the beacon to somehow trick a bunch of X-Wings from murdering the station. Not a lot of it made any sense. There's, like, six different shots of the droid hunting down Baby Yoda on the ship that add absolutely NOTHING to the story and just go on forever.
It's not that I don't still look forward to new episodes, but with episode 6, The Mandalorian has gone from "must-watch" to "flawed but watchable." It's the kind of drop you'd expect between seasons 1 and 4, not across a short self-contained season, and it's a damn shame.