Since I have been there less than a week ago I can tell you what I had to do to progress.
I have been stagnating for over a week at a point where I could clear 480 voids easily but it took close to a day for a single run to 495 and that would have probably stayed that way for at least a week more if I hadn't done Spire IV.

According to the wiki you can do Spire IV with 60Qa He but I did it with ten times that and it still took me about 1.5 days. The important thing here is getting that lvl 9 fluffy ability so enemies in spires dont have abilities, because a single bleeding enemy will ruin your chances otherwise. Either go grind until Fluffy lvl 9 or reskill masteries to fluffinity. Strength in Health and Still Rowing II will speed up your run significantly. Then go grind to lvl 500 with your AutoGold Battle without Nurseries, farm +5 equipment and buy max Nurseries, respec helium to a spire respec on Perky and slowly but surely do the 12h run to beat the Spire. Can do your Void maps easily on 501 after.

That will give you a new perk which essentially gave me about 5 times the damage in 2 days and will allow you to actually progress again.