Games as complex as Baldur's Gate 3 rarely have clearly-defined 'good' or 'bad' endings for characters. There may be an agreed-upon evil route through the game, but the choices the player makes for themselves and their companions can't really be called good or bad as it's a matter of opinion. There are several companion characters that will accompany you through Baldur's Gate 3, and their fates largely rest in your hands.
Baldur's Gate 3: Should You Let Astarion Ascend?
If you're struggling with whether you should let Astarion ascend in Baldur's Gate 3, this guide can help!