On another note, I recently updated my iMac to High Sierra. Editing is now slow & laggy. My distrust is @Apple grows. I honestly believe they do this so we must upgrade. I no longer use an iPhone. Might I switch computers too?
I'm running a Mac pro from 2012 with high Sierra with no issues. The new version is faster but I have upgraded to a SSD and 32 gigs of RAM :) but I do think a PC build is better bang for the buck these days.