It was marketed as a Turn Based Close to Tabletop D&D Experience. We are not getting that. End of story.
Is there a source that says Larian wanted to create an authentic TT RPG? [...] I don't remember Larian guaranteeing or even promising such a thing.
I tried to answer that question in that post, a little while ago (motivated by a similar question from someone else). My understanding of Larian's vision has probably improved since then, but the core of my post was looking at 4 interviews Larian gave, where they talked about the rules and the DnD/tabletop feel, and what they said won't change.
I wasn't able to provide a definite, clear-cut, yes/no answer to the question. But I found their communication to send mixed signals, saying both "it will be quite close/just some tweaks" and "oh we only focus on a game we'll enjoy playing, not so much on the RAW". And I think that it is very understandable that, as a result from Larian's communications, some players were expecting more faithfulness to the rules.
After I read your post, I thought more about the fact that they directly said that all DnD rules will be changed. I think the main argument is that they never said that would be absolutely accurate, so any change on their part can be justified. It is likely that the players only saw what they wanted to see.
Also about this guy from stream...
I watched the entire stream, obviously they called him in to show that WotC supports their direction. And in fact, BG3 really helps them, many people who were not interested in FR will now be interested more.
