As I like my RPGs singleplayer and storydriven I agree with everything you have written. I do think Larian did a much better job in making BG3 feel less like playing a Coop game by yourself, but many of its designs make sense only, when you consider it a playground for a couple of friends to have "lols" in.
Having "open world" design, and yet have everything so disconnected has been bothering me since D:OS2. Again, I don't think BG3 is as outrageous, but even if this time around some thin connection exist each of them still feels like they exist in their own bubble. Perhaps, an abstract x hours long travel time on world map, would make it feel more natural. Larian design gives me 1917 feels - where one shot approach felt more distracting and artificial then immersive. It makes sense from coop design - keep all players in the same location and not have to "gather your party before venturing forth". but IMO it doesn't feel good.
I think one needs to accept that Larian makes coop RPGs. It's just sucks that Larian uses Baldur's Gate IP to do their own thing.