After a few hours of trying to not end up with either multiple dead party member or being de-buffed to something like 1 Dex I gave up. I almost couldn't hit it at all. Even with Arcane accuracy. If I did then the attack did something along the lines of 10 extra damage only on crits it ever got up to 30+.
But funny enough I now read that there is an AC stacking bug for enemies with the newest patch. Though I'm not sure if the worm was affected by it and I think Dex Scion attacks are touch anyways?
I will give it one more shot to play on hard before I need to realize that I'm not good enough for that yet. Even though challenging did feel a bit too easy. I did learn some stuff about positioning though so that's nice at least.
You mentioned it's okay to go monk whenever in the first 9 levels in your Sylvan Sorc build and I feel like I would profit more from a stronger pet and stinking cloud earlier. Would be taking it after getting stinking cloud truly okay? I never really felt like my Sorc was focused anyways and didn't really need the AC.
Also one last question: Do Saint and Trip Vivi have a stronger early game than Dex Scion?
Depends on what you want. If we are talking tankiness - no, not at all.
Generally earlygame is pretty scummy on unfair and amounts to hiring a sylvan sorc halfling with mage armor and grease. Then you proceed to ditch everyone from the party to level faster with you, valerie and sylvan sorc. Will take quite a bit of reloads, but hey, it's not like there are many options when you get one-shotted by anything.
Also visit Old sycamore before tomb. It has quite a bit of stuff to kill that will vanish when kobold/mite conflict starts.
Melee starts are hard. Str ones have meh AC and Dex ones have no damage.