Real use example...
Raspberry Pi 3+ using the RPi-JMRI image four throttles seems to be the limit we see... more than four and "I've lost control..."
Given the assortment of old 2.4GHz only routers from decent sources like TP and well under $100 I'll agree that if I'm looking at both more than four throttles and any sort of larger or challenging space... HVAC or L shape space I'd go with the router. Not hard to set up and doesn't need connection to internet.
Done that here but with ancient PC.
Jim Albanowski