Oh the usual "if it doesn't exactly fit my own personal point of view about what dnd is then I don't accept it".
I love the game. It has dragons, it has dungeons. By pure logic this is a dungeons and dragons game.
Just in case it is not clear enough, Dungeons and Dragons doesn't refer to actual dungeons and dragons, but its a title of a game with an established ruleset and lore on which BG3 is based on (the 5th edition of the ruleset specifically). Whenever game has dungeons or dragons is actually irrelevant. Many games have dragons and dungons and are not DnD. I am glad you are enjoying the game though.