Bad news first, you can't skip Act I without cheating. While you theoretically can just do the main story, leaving out much of the overworld and all of Underdark in Act I, the overall result would be entering Act II at a too low level to succeed there. So what I did was use a general cheat mod called WeMod (I'm sure there are others too) at the very start of the game to give me 16 times more xp than normal during the tutorial part on the ship. That got me up to level 5, at which point I disabled the cheat mod and played the rest in a regular way.

Now my next problem was getting a party. Nothing keeps you from meeting Shadowheart, Astarion, Gale, Lae'zel, and Wyll like in any normal playthrough. But I had decided to do an evil playthrough, using The Dark Urge. And I wanted to play him *really* evil, not as a good guy trying to suppress his dark urges. That was both to see some consequences I hadn't seen yet in my regular playthrough, and because siding with the goblins against the thieflings and druids is actually faster than the other way around. But the companions with good alignment run away if you do that. And as I had collected all the companions in my first run, and done cutscenes even with those that weren't part of my regular party, I wanted to do a run without *any* of those companions (though I might pick up Minthara later).

What I did was use my level 5 character solo to enter the Dank Crypt under the Overgrown Ruins through the hatch in the east. Then I just needed to solo the skeletons to unlock Withers. Having him in the camp then allowed me to get hirelings instead of companions, which are characters without dialogue or story. You can't build them completely freely, but there are 12 different hirelings covering *all* of Baldur's Gate 3 character classes. So of course I made a group *without* the standard fighter, rogue, cleric and wizard. Using a group with different character classes was more interesting to me.

Now I could have simply sneaked into Act II like that, but I wanted to have at least the main quest of Act I finished to the point where it tells me where to go to in Act II. Now the first battle between goblins and the grove is unavoidable, and you aren't able to pick sides. I just started that battle and ran away, and still got treated by dialogue later as if I had helped. The grove still wins without your help, although with several characters including Wyll dying in my case. Which was fine with me, I'm the bad guy here. By running away and doing a long rest I managed to basically skip that long battle. Then I came back, entered the grove, freed Sazza (not strictly necessary) and got her out through the secret tunnel. With her help it was a bit easier to enter the goblin fortress peacefully and get to Minthara. There I chose the dialogue option to do as she wanted and help the goblins destroy the grove. Back to the grove I needed to do another long rest and talk to Zevlor on the gate to get the option to betray him and start the second battle on the side of the goblins.

While this leads to a potential sex scene with Minthara, you don't get her as companion at that point, but only much later in Act II. But she does tell you to go to Moonrise, so you basically get the same main quest goal as if you had freed Halsin and got the information where to go from him. And this was all I had to do in Act I. I didn't have to kill a single goblin, didn't have to do the north or the south of the Act I map, and didn't have to do the Underdark. I can access the Mountain Pass of Act II through the entrance at the goblin camp, and not bother with the githyanki or the duergar. And while of course I don't get the loot of Act I, the nature of the game is that the loot of Act II would have replaced the earlier gear anyway. Overall I just needed under 3 hours to "finish"/"skip" Act I and have a viable party to properly start playing Act II. But that was just an experiment, saved for maybe later, and I'll go back to my first playthrough with good alignment and companions now.