No worries. I did pore through the above thread but that's not a concern for me or my company's work. Primarily, I work only with OS's and hardware certified by my SW vendors, IOW if they don't test and certify a hardware/OS combination I don't upgrade an OS or swap hardware - keeping my billable production optimized is my goal.
On my end, when "iCloud" came out a few years or so ago I noted that performance of our Macs and PCs (with that iCloud Control Panel installed) tanked, big time. I make one change to any computer configuration at a time so I can put my finger on the one issue. VMs help with this. On pretty much any computer connected to "the internet", that connection is the bottleneck - eliminate the bottleneck, QED. The resource killers on your Mac with iCloud "turned on" are Mail, Safari bookmarks, Photos Agent (this one along can spike to over 300% of CPU usage and can stay pegged near 100% for an entire session), and iCloud Drive (which is still buggy). Just look at your Library>Mail>v4/v5>MailData folder - all of that caching along can cut your Mac's I/O performance.
I work with AutoCAD, have for almost 30 years. It is a very configurable beast, and it's relevant here. AutoCAD is an app that is installed locally, on a hard drive, and communicates with a license server (to make sure you have a legal copy). It's extensible, just like your Mac's OS. It "talks" with multiple sources simultaneously - a source (or base) file, XREF files, a license server, a printer/plotter, and any other networked computers that may be linking to the base file (if it's on a network) or the XREF (externally-referenced) file(s). The production killer here - here's the key - like Photoshop, AutoCAD uses proxy/swap files and both applications allow for isolating Every. Single. Workflow. Element. in a workflow. I used Windows Explorer once to watch how AutoCAD deluged a hard drive with swap files during a simple drawing session - the drive was choking on trying to process the work, create and reference swap files, communicate with the several different network feeds, and put a graphical representation of the work on the connected displays. That was 15 years ago. Now, on top of that, add in email/Photos/messaging/etc./ad nauseam that are both creating their own caches AND verification server(s) - and cram it all through one bus on your computer. Ugh.
Read though the posts here in this forums about slow interfaces, laggity laggity lag, and issues with OSes. I have none of those issues, and I'm frequently working with only a cellular connection at one of my field offices. In my experience, all of iCloud's I/O is killing their performance. My first proof was by using a 2009 iMac with a 7200RPM spinner but I've born out the same postulate to my business partners with zippy SSDs. So, no, it's not High Sierra or any other OS issue - it's all of the added features that need to be turned on/off that can kill a production workflow. I interface with my business Apple/Microsoft/Autodesk reps, they're aware of most of the bottlenecks and they'll offer much of the same advice that I'm alluding to here. Turn off unnecessary services - a no-brainer, as is offloading services to another computer or VM. I have that Mini in my home office, it's got 5 different renderers installed - I drop a file (AutoCAD DXF, MicroStation DGN, or video project) into a folder/directory and it takes the load off my main Mac.
iCloud is a mainstream sync service. iCloud is not a professional-level sync service. iCloud can seriously hamper the productivity of a business computer, and...
What I like about VMs is that its user can completely isolate it from every other service (including "the internet"). You can put that VM on a fast SSD RAID and connect it to your Mac/PC to GSD (Get Shi..., er, Stuff, Done). I use two Samsung T5 500GB SSDs as my swap/cache/project/VM swap file drive, with the two T5 drives mounted via two USB ports - but they're configured in a RAID 0 configuration, so they're seen as one 1TB drive by my Mac or PC; this "drive" talks to my VM and rendering/processing is done in a fraction of time, for two reasons. This RAID 0 drive communicates through 2 different USB buses AND it carries all of the swap files generated by what app I'm using and utilizing a different bus than the bus that serves my internal hard drive. My throughput on this "drive" is pretty zippy, got the tip from Barefeats several years ago on this bit and made a few tweaks of my own.
Over and out. Cheers.
