I just updated a moment ago to 2.1.1. I have been warned of a tech cycle error (water-washing-1) leading to (water-washing-1). Cannot load game.

Specifically:
water-washing-1 (top level; rest are nested)
angels-sulfur-processing-1
slag-processing-1
omniwaste
omnitractor-electric-1
omnitech-viscous-mud-water-omnitraction-1
water-washing-1 (this is the cycle)

I have found the offending mod: Omniwater.

Without Omniwater, the omniphlog machine is gone. It appears that the many omnic water recipes are not able to be used (e.g., molten copper to omnic water, real water to omnic water, purified water to omnic water).

In my old save, the omniphlog was critical to the omnite production scheme. Now, omnic water can only be obtained from the ground (the omnic tower-like thing) or from the omnic drill(?).

yes, omnic water should be only obtained from the cooling tower and the omnidrill (thats why pumps are disabled).
Sorry for the problems with omniwater though, i didnt test full compatbility with all omnimods yet.

Edit: The issue with Omniwater is fixed in 2.1.2, looking into the rest on friday

How do I submit a private message?

Not possible on the modportal, this is Omnimatters discord , you can ping me there if you want:
https://discord.gg/H786nrS