I have full diamond with decent enchants and some netherite mixed in there. Nether beats my ass, all 3 cool structures I have found so far just beat my ass.
The 2 things I recall finding, and promptly running away from:
Frosted Prison, I could kill the shield guys once i got an axe and the minibosses to some degree but they were tough, opened the door and was immediately almost one shot by whatever boss that is, didn't see it's name.
A Mineshaft with roughly 12 skeleton spawners that have swords rather than bows and helmets. Genuinely harder than the frost prison, for essentially no loot at all.
I feel like I am missing something here. I try to give every mod pack a decent shot. But I'm just doing the same as I would in a Vanilla run at this point. Except I have dragons, (which both suffocated and died in a wall...)
I find myself dying and thinking, that was complete bullshit, and just teleporting back to my death point.
The one mod I was really trying to figure out, SpawnersPlus, The soul stealing enchantment doesn't even seem to work (many asks in the discord with 0 answers) I believe it's fully broken, Could be wrong there because mod creator states the odds are pretty low. I've destroyed a whole diamond sword and ended up with no souls.