They basically weren't aware of the game before it got GotY and some even got sour that it won more awards than Zelda. (There was even a forum thread named something like "[sad news] a game that no Japanese has heard of has won GotY" which was quite hilarious.)
Then after the launch many players are surprised of how much freedom the game provides, and enjoy multiplayer sessions, classic big explosions, Talk with Animals, Scratchy the dog and Grease + fire combo, etc. There were some players that dropped the game with weird reasons tho, from "not anime enough" to "I thought this was an action RPG??" and even "I like RPGs but not TRPGs (??)" I'd say BG3 seems to be more like 50/50 in Japan because how its structure is different from JRPG's, but those who enjoy the game are really fond of it.