Hey DC
It’s not very clear, but I was suggesting that with the TP-Link Deco M9 Plus (and maybe the earlier M5) they are conceding that the ‘mesh’ setting and programming is better designed for a device ‘orchestra’ than an eccentric ‘quintet’ like mine.
Maybe the user is better equipped in some cases to fit the system to the situation than fancy dancy auto-logic. At least he can be given the opton to contribute based on real world observations.
Engineer’s ideal:
Secondly, we need to reiterate what is the point of having a whole mesh Wi-Fi system in your network. The whole point of mesh networks is to give a seamless, unfettered, and performant experience for wireless networking, and thus a mesh network is “self-configuring” and “self-healing”, the network automatically incorporates a new node into the existing structure without needing any adjustments manually by a network administrator and it automatically finds the fastest and most reliable paths to send data. If you change the wireless channel on the Deco nodes manually, it may give you the risk of losing the other Deco nodes and thus ruin your Deco system, you may need to start over again to reconfigure them. TP-Link Support, late 2020
Evidence of concession:
I was also thinking that the mesh logic of your newer, high-end Deco XE75 Pro is way more sophisticated than that of my M9. Though @woodyk34 's report of the even older M5 meshing nice with 14 nodes and sundry devices undercuts that thought a bit. 