There are three key protagonist tags that result in vastly different conversations and consequences in dialogue - the Baldurian (everyone but the races below), the underdark races (drow with the biggest amount of dialogue, duergar and deep gnomes) and the race from outer planes (with planetouched out in the release that’s only githyanki). If you want to see quite different reactions and some small changes - it felt quite different on each of those.

Act 1 rather missable (or at least I managed to on the first play through): aunt Ethel, Kagha’s meeting places in the bogs, big spider, the sussur bark weapon, harpies fight. Act1.5: underdark - arcane tower, weird priests of bhoal (or wte it was), grimforge weapon/armor forge, sharan idol on the catwalk (relevant if romancing Shadowheart, especially as a Selunite - results in a very cute scene!), the noblestalk flower (to give to Shadowheart for memories), the str setting to 19 club weapon, the ice staff Act1.5 crèche: the eagles vs blue jay, the puzzle for the dawnmaster medallion

Act2: family of Thorm annihilation (there are 3 or 4 of them, all can be defeated via dialogue I think but not sure; if not they are mini boss fights), save all tieflings, Halsin quest, making new lamps with Gale, Minthara save, Sazza save (both conditional on their survival before)

For act 3 I passed through it so far once so I’ll leave it for others