Welcome to the forum, sorry you’re having issues!
I’ll second the recommend on .6 Nozzle. That’s been the recommendation in the 3D world for any filled filaments like CF, Glass, Wood, Metal Filled, some Marbles, etc. for some time.
Nozzles should also be hardened for those materials as they’re abrasive.
As for the Support ticket, be aware due to the viral sales of this printer they found support was quickly overwhelmed. They are training new staff and adding support infrastructure, but it takes time to setup, so some of the staff are pretty new.
Not making excuses for them, just giving you a heads up of the real world situation. 
Keep after them, they are usually pretty good if slow. Most often they give a Store credit for it.
But absolutely get a .6 or of they’re big parts, even a .8 nozzle. You might also check out this long discussion on the new CHT nozzles which BL hasn’t gotten implemented but I suspect are coming in later machines.
They allow a much improved flow:
https://forum.bambulab.com/t/first-benchy-printed-with-bambu-lab-x1-cht-nozzle
Another things you might wish to read up on is OrcaSlicer if you haven’t found it yet. It has some more advanced settings than BL Studio and more importantly a bunch of two and three click Calibrations that Studio hasn’t gotten yet.
I did a PSA about it here: PSA Up your Game Studio, SoftFever OrcaSlicer, & Arachne - Bambu Lab Software - Bambu Lab Community Forum
Cheers!