BG 1 and 2 were games presenting adventures in the D & D Forgotten Realms, specifically the Sword Coast region, using substantial aspects of the 2.0 rule set and lore specific to the territory, characters, magic, bestiary, and history of that part of Fearun.
BG3 is a game presenting adventures in the D & D Forgotten Realms, specifically the Sword Coast region, using the 5.0 rule set, and lore specific to the territory, characters, magic, bestiary, and history of that part of Faerun.
While YOU may not see enough ties to that prior lore, they are there - and once we get to a full game, and not 10-20 % at best, will surely be there to a greater degree.
So it is clearly BG3.
Being BG3 does NOT require reversion to 2.0 rules (and I for one still am a fan of 1.0 and 2.0 rules), does NOT require it to return to the same protagonist, and does NOT require it to hold to the exact same technical/mechanical rules. BG and 2 utterly ignored the 3rd dimension - you could not climb to a roof, rappel down a cliff wall, swim down a river and so on. Games now allow for such interactions with the environment - should BG3 be forced to limit itself to only what existed back in BG1/2 era? I personally enjoy the IDEA of fire doing more damage in a flammable environment, and electricity doing more harm to someone standing in water. Do they have it down perfect yet? Maybe not, but there is still plenty of time left to perfect it. Do I like barrelmancy? Not to the degree that initially existed, but they are already toning it down - and again, I don't have a problem with blowing the crap out of a brewery, where a big huge vat of alcohol is appropriate - rather than a privy (though certain gasses tend to build up in those old school privies that might operate in a similar fashion). I am happy to watch BG3 explore the impact lighting, elevation, terrain partial cover) and the like as they are being implemented and tuned - none of which existed in BG1/2.
Nor do I expect the vast majority of characters from BG1 and 2 to still be alive and kicking in BG3 - 100 years have passed after all, in the equivalent of the middle ages - not an era known for longevity (at least in humans).
If you decide to have a child, you don't get to return him/her if they don't grow up the way you like, and get back the money you spent raising it.
If you decide to buy a game in EA, essentially a child, you don't get to return it because you don't like the way it's turning out either.