ATMOS channels on Mac mini

Sorry for the likely breach of forum protocol, but had problems trying to post to a sub thread, so here goes nothing:

Specifically I have a couple of questions regarding running REW(V5.31.3) on older MacMini (2012/i5/Catalina) and implementing higher channel count Atmos (7.1.4).
The signal chain is Mini + two sources > Onkyo RZ740 > MiniDSP HTx+2@2x4HD for processing of 11 channels and 2 independent subs. It works, but is rather clunky.
- Can REW’s Soundcard preferences accommodate higher than 7.1 if the attached computer is configured for such?
- It’s my undertanding that the Audio MIDI on latest versions of MacOS ( Sonoma and forward) can achieve up to at least 7.1.4, but does anyone her know of there are minimum chip and RAM requirements for that capability? I’m hesitant to patch either the Mini or older MBP via OCLP if they’d still be hardware constrained.
Thanks in advance for any guidance.

The additional channels ATMOS provides are decoded in the receiver. REW cannot generate or access them directly as it does not include an ATMOS encoder, which is a licensed Dolby product. ATMOS channels can be measured using file playback, there are files here.

Thanks John, exactly the answer I needed.