I loved Grymforge!
Tried it for the first time during Patch 8, as I try to pace myself on new content. My run breaks down into four parts. [Every spoiler from here on out.]
First, clearing the deep dwarves who stand around in single encounters. These fights are fun, snappy and rewarding. They’re also pretty great when trying to fit three or four jousts between long rests.
Second, fighting Nere along with everyone in the world. I didn’t know it was a glitch, so I rolled with it, which landed me squarely in a lava pit. My second try did it; it was a glorious 12 turn slog during which the barb raged twice and Silence was useful for the very first time.
Third, finding the forge. That was the most thrilling part of the experience. The fact that maps are so condensed was used to great effect to turn me around. The corridor of flames roasted me alive and I was ambushed a few times. Genuinely wondering what was around the corner was great.
Fourth, defeating the end boss. The build up felt appropriate and there are plenty of neat surprises before encountering the big bad. I think the OP might have been experiencing a glitch. For my part, I had the solution spoiled for me somehow, negating the sense of discovery I value so much.
Overall, I enjoyed the dicovery, the challenge and the change of pace when looking for the forge.
It makes me wonder how much replay value I’ll get from BG3 if I can only find that sense of wonder when discovering a new map.
Edit: suggestions for the Nere fight.
Fundamentally, combat can break down into action economy. Winning is about using your actions to negate theirs. Use your turn cycle to ensure you kill an enemy that hasn’t used their action yet.
Shatter is great for nuking a bunch of gnomes at once, which reduces the enemy action pool. Hex + Scorching Ray can one-shot anyone. Magic Missile with that one amulet can surgically remove actions from the enemy pool.
The other way to waste enemy actions is with good defense. High AC or high HP (or both) means your PC requires many enemy actions to take down. My 20 AC Bearhart Barbarian worked a treat in that respect, but plenty of other builds are viable, if that’s what they’re intended for. And if you want to protect a vulnerable character at the start of a fight, invisibility is great.
For this fight in particular, there is high ground from which casters can wreak havoc. It’s up a ladder, just to the right of the rubble you clear to trigger the fight. I recommend casting Feather Fall at some point on your PCs standing up there. Enemies are just as happy to shove you off the ledge as they are to shove you into lava.
Finally, don’t be afraid to use every last ressource at your disposal. If your tank won’t use their bonus action this turn, coat their weapon in poison. Use that scroll of Aid you stole from the druids for no reason. Good gear helps, too. You need to give it everything to teach those deep dwellers who’s boss.
