The stuttering / freezes / terrible frametime. I'm not sure where it come from, i made a bug report about it (#773368) - it's bad, i often get 500ms+ frames offline and it's sometime worst online.
This is what two quick offline interchange look like with an 8 core ryzen at 3.8ghz, 16gb of memory, game + system on different SSD and an RTX 2080: https://image.ibb.co/m4UWPf/frametime.jpg
you understand that if it was widespread everybody would notice that. something is not right on your end. write the ticket number plz