Yes, ColourSpace is presently Windows only.
That is stated very specifically on the website.
It is also stated on the FSI website.
(And as you purchased via FSI they are your direct support agents, and do provide very good support.)
VMware Fusion is free, as an alternative to Parallels.
And there are plenty of low-cost (even free) ways to get Windows 11.
Google will help you there.
For example, it is possible to legitimately download and run Windows 11 for free, with some customisation option restriction.
But that will not affect ColourSpace operation.
Steve
Steve Shaw
Mob Boss at Light Illusion