The fact that you didn't find it fun is totally valid. BG3 is a very opinionated game that gets a huge number of things right for its target audience - the people who really enjoy CRPGs, branching paths, and choice driven gameplay. It does sound like that you're really not into those things, so BG3 could never have been an excellent experience.

The games that you list are designed to be mostly linear experiences, so it was possible for the devs to make the core gameplay shine because they had time to really polish those systems and interactions. There was enough people and time to really tune RDR2's gunplay, the horse riding, the hunting and tracking, and make the world feel organic.

BG3's dev time was spent on tuning the combat encounters, tuning the class building options, and making sure the world (almost) always made sense. While baking in hundreds of stories about your companions, side characters, abusive store owners, and lost puppies. The game never holds your hand, only asks "here you are, this is what you've done, what do you do now?". The amount of effort put into respecting the moment to moment choices made by the player is staggering.

The complexity in these systems in BG3 left preeetty clear issues with things that would otherwise have time to be polished out of a game before release (animation jank, visual bugs, pathing, pausing). For me, they were more like bumps in a very scenic road. But I hear you when you come in expecting a shiny polished RPG but there's all these fourth wall breaking bits that kind of stall the whole show every like 5 minutes.

I think there's enough nuance here to have both sides of the coin be true - it's an absolute masterpiece for the players who enjoy the specific experience it offers, and it only makes sense to feel it's overrated when you're coming in expecting a cinematic or visceral experience.