Xanathar's "guidance" for magic item prices is woefully under baked. The amount of gold given out (even in standard, official 5e adventures) makes purchasing even the most potent magic items possible with pocket change.At first I thought you were joking for the adventure not following those rules, but your next item makes me think you meant it... see Xanathar's Awarding Magic Items
They haven't gotten to the tomb yet. So far it's dealing with cultists and mostly human adversaries. Even high level casters and warriors die in a single round.Don't know the adventure (apart from reading the description), but I expected the majority of it to be in, well, a a tomb / pyramid. So do you not manage to get that many encounters in then? Worst case, make them bigger encounters (higher CR, more monsters) rather than more. I also thought there would be traps etc., The description sounded like it was meant to be challenging, so I am surprised it is such a cakewalk.
I had 25 enemies on the board, including some high level casters. They could do nothing ... as worthless as goblins. Dead in one round. Got off one buff spell before death.
I think Old School designers woefully underestimate what challenging means in 5e.is he ? "Necropolis is designed for a party of 6–8 seasoned characters starting between 7th and 9th level and will challenge even the most experienced players."
Given the level range I assume we are talking about this one
Honestly, I doubt the system works at all after 6th level or so. (My group hit the limit of challenge early due to its size.)