So far, everything runs well after installing updated plugins for the offending parties, worlds come up to 1.18 as expected and play well from different client versions by the way of ViaVersion.

The plugin that is still awaiting an update is Worldedit- unsupported version error... while some "old" and "outdated" plugins rock out fine.

The only game thing that I have seen is a memory need increase@ my lobby server of about 1/3- went from 2g4g to 4g8g and have had no issue with ticks warnings since. I'll let ya's know more if it gets dastardly. For now I'm considering a parallel 1.17 server set just to be able to continue. The machine can deal... I'll drop something else (cataclysm) if I need to in order to do what I want as this is a free and personal venture but still... should it be necessary?

Well... I dropped some jars and they broke everywhere... picking up the pieces slowly. plugins not on api are the culprit atm.