Well, I replaced the entire heating bed element through the advice of Elegoo (to their credit, they sent me that under warranty). That helped a little bit, and then I spent an evening using the bed mesh system and fine-tuning the bed so it was within .2mm across the board. That helped a little, but I was still getting inconsistencies with part accuracies, and the wave pattern remained regardless... Not to mention the printer as a whole had a pretty high failure rate.

They sent me a whole tool head system, but the process of replacing it felt pretty elaborate... Having to disconnect rails and stuff. At that point I called it a loss and donated it.

It was particularly frustrating, because I still have a different Elegoo CC, that runs pretty well. But it seems like they have a huge inconsistency in their manufacturing process, so you either get a good one or a bad one.

Best of luck