@flips01 My recommendation is to leave the default management subnet AND VLAN alone for minimal fuss and bother in the future. You can change them for sure, but it's more bother to do it for setup...

Apple support article HT202628 does a reasonable job of explaining the technology. 80211.k and .v have to do with building lists of suitable 'roam to' APs 802.11r facilitates a rapid transition...

@Xa13 Without knowing exactly how the 3rd party router is configured, I can't be sure, but I suspect it may be at least partly to blame. Do you know if it NAT's your two WAN options? It would be...

@greenmyrtle You can re use any existing POE switches you might have, unless you want cloud management of ACLs between VLANs--which is unlikely? If you do replace switches, they must be Omada...

^^ AI babble.

That's great news! Thanks for your persistence and for letting us know it worked for you.