That Jason Momoa Conan movie just came free on Prime and its been a while so I gave it another view. It's not great but if you put it side by side with Arnie's its actually pretty good in comparison. Why didn't Conan fans like it?
It's a decent swords-and-sorcery film, it's just not a very good as an adaptation of the Conan stories, or at least how people have come to think of the Conan stories. Tonally, thematically, and aesthetically, it feels a bit too much like a generic contemporary fantasy film with the Conan name attached; it's almost a little surprising that it was in production at the same time as
Game of Thrones, because it feels so much like an attempt to cash in on that series, and not simply because of the star. I quite enjoyed it on those terms, but I can see why somebody might react more negatively if they feel it as being delivered
instead of the more faithful adaptation they might otherwise have had.
The Arnie film honestly wasn't much stronger as an adaptation of the Howard stories, or even the Marvel comics, but it does more strongly channel the barbarian adventure as a
genre, and so is looked upon more kindly. Arnie's Conan has more in common with a generic
Dungeons & Dragons barbarian character than with Howard's Cimmerian, but that at least places him authentically in the context of seventies pulp fantasy.