What do you mean by root patchens?Just to be sure: You applied the root patches, didn't you? Because "very sluggish" is not really what I would call the Big Sur and Monterey machines...
To be honest my experience is ~>1 year ago. I updated witout OCLP and the system really was not usable for me.
Has there been progress in GPU acceleration?
It seams like that by reading https://dortania.github.io/OpenCore-Legacy-Patcher/MODELS.html and https://github.com/dortania/OpenCore-Legacy-Patcher/issues/108