I just bought a Parallels licence because I have M1 and VMWare doesn't work well on this. Linux guest support works great, but the MacOS... well, let's just say I'm glad I didn't buy it for that.

I think it should be more labelled as "early preview" or something.
What I can do:
* Create a VM with MacOS but absolutely no customization (although Parallels seems to make it hard to customize before creation even for Linux guests, I have to create a VM and then change it).
* VM had 16GB RAM and 4 CPUs (my host is 64GB and 10 CPUs so probably about right; I don't know if it adjusts based on host)
* Launch the MacOS guest, access the network etc.
* Sound etc. was working, I can see in About my Mac
* I managed to install Adobe Creative Cloud and launch Lightroom Classic
Issues:
* Resolution is fixed (I've deleted it but I think it was like 1440 x 900 or something)
* Feels very sluggish compared with Linux guests (I'd been using Ubuntu aarch64)
* Chrome browser is unusable, address bar corrupted along with the top 15-20% of the web page area (all web pages, even Google)
* Safari is slow and seems to do nothing so I type another address and then some seconds later the original site pops up; otherwise seemed usable. Didn't look into it further to see if it's network related, although downloading Lightroom was fine so if it
is network, it's probably DNS
* Managed to crash the host (only time since I got my new MBP a couple of weeks ago that it's crashed) while exiting full screen
* Unable to rename the VM from the default "macOS 12" (no option in Parallels, rename on disk and it can't find it)
If this were usable I'd want to look at remapping some shortcuts, because things like cmd+tab and cmd+space apply to the host (on Linux guests the PC-style shortcuts don't tend to clash as much). I'm not sure if there are some good default alternatives that I needed to discover (slightly random example but Microsoft remote desktop is good for this when connecting from Windows to Windows), or if the user is expected to come up with their own.
This is a really interesting tech preview and kudos to Parallels and Apple for making it happen. I hope they'll develop it to a production-ready state because it could be quite handy to do some work in a VM that can be restored or wiped afterwards. I also wonder what licence restrictions apply - I understand we're supposed to only run macOS on Apple hardware, but will they let me have a couple of macOS VMs running on my Mac host?