I do believe Ryukishi massively second-guesses himself, but much of Episode 8 is indeed about Umineko itself, and the relationship between the work, the creator, and the fanbase. Don’t get me wrong, of course I love and respect the man, but Erika and the Goats are very clearly meant to be representative of parts of the fanbase. While Ryukishi has always had a close relationship with his fans, due to this close relationship he’s also witnessed a lot of terrible, bullying responses from readers and netizens- To the point where he almost stopped writing Higurashi after Ep6 due to 2chan’s response to it. The way the public responds to the Rokkenjima massacre is very clearly meant to parallel the fanbase, and I think Erika’s reactions to the Love Duel in Ep6 also establish a parallel with many of the readers at that time.
You can totally argue that the Trick End (since we are perhaps leaving the Bad End term out of it) acknowledges that there’s no wrong option, but… I disagree. The Trick End is portrayed as the wrong option, as in, the events that occur in it are wrong to begin with. The setting is wrong, being in a situation that’s been established as impossible, Ange’s actions are wrong, both immoral and irrational, and she’s being equated to a character who’s downfall was being so sure of herself despite being completely wrong.
I won’t use the term Bad End in fairness, but I personally do think of it as a bad end. In the Trick End, Ange refuses to learn anything from her experiences, and comes to the conclusion that “the truth isn’t worth anything.” So, she ends up living in a scenario in which there is no truth, sliding into complete unreality as shown by Erika physically manifesting with her on the boat. I don’t think that the Trick End is badly written at all, but I do think it is a “Bad End” in that it isn’t a happy ending, and I do think it is meant to comment on the kind of player who would pick Trick over Magic.