I suppose you're responding to the "render farm" photo in the Mac Mini blurb.
All this is is using Thunderbolt 3 to create a very fast network connection between Mac computers.
Specific apps can make use of this very fast network (or even a regular Ethernet network.)
If you have specific apps that supports this, it can take advantage of it. If not, no.
There is no magic built into the OS that makes creates some "super computer". It's just an app farming out some of the work to one or more additional computers.
A TB3 network allows data to be transferred between the computers faster. The same capability is available without the TB3 network, just slower data transfer. And has absolutely nothing to do with either the OS or the hardware.
Nor is this limited to Macs.
It all depends on the app. For example, some Adobe products support this:
https://helpx.adobe.com/after-effec..._still_image_sequence_with_multiple_computers
Depending on the product, this can become EXPENSIVE due to licensing costs!