I see complaints like this as similar to the way people feel when an IP based on novels or comics becomes a film, and is handled differently by different directors.
For example, you may prefer Christopher Nolan's take on Batman in the film to the way Tim Burton handled the character, but it's just the same underlying IP being handled with different tastes. The core concept of the caped crime-fighter remains.
Larian isn't Bioware, so naturally they'll have their own take on the Baldur's Gate IP. As long as there is a "family resemblance," and I think there is, that should be good enough. At least it is for me. You just have to get used to the new direction, the same as when a favorite character is handled by different directors in a movie franchise.
These are fair points though one thing I would suggest is that movies are a more passive endeavour than playing a CRPG. We do not get to make decisions while watching a film that affect how the film plays out (apart from those rare interactive movies).
You are right though, the core concept of BG remains fundamentally the same in BG3 ie. a party based RPG set in DnD universe, but for me a vague resemblance to the prequels alone is not good enough to honour the legacy of those games.
Like the OP I have also struggled to fall in love with this game. Nostalgia probably has a hand in tainting my experience but nevertheless after my initial and considerable excitement at playing BG3, the novelty soon wore off when I found the combat to be repetitive, classes felt far less distinct, the map felt like a series of corridors ushering my party from one encounter to the next, the infuriating party control system, cluttered UI. There was no night time, no weather, hardly any animals in the woodland areas, the world didn’t truly feel ‘alive’ to me.
Don’t get me wrong, I did enjoy playing the game but it hasn’t seduced me like the originals did. I understand this is a purely personal experience; some posters are already exclaiming this as the greatest game ever made and it seems to have spawned an entire industry of Astarion and Shadowheart memes...whatever floats your boat. I suspect I am not truly the target market for this new iteration of the BG series.
I often wonder what would the community response be if another studio took on the development of DOS:3 and changed many of the facets of that series that made it so popular?