Two X10s One in AP mode 802.11s supported?

I did post over there. Apparently, there is no way to route an SSID so it can talk to the default wired network. I could configure the admin wireless for everyone to use, but it doesn't support SSID separation, and I need different SSIDs for 2.4 and 5ghz as several devices on my network refuse to connect with the Orbi deciding which network it belongs on. I tried this on the X10 as well, and everything connected to 2.4 no matter what.

So, if I left the second 10x in router mode, not AP mode, how could I accomplish what I want? It doesn't allow me to choose a different class C address range, so I would have to do a /26 or something for the DHCP on each. Considering the load between them isn't equal, and devices would move from one over to the other, they would lose their connection anyway because their source IP address would need to change when it connected to the second X10.  I really don't understand why the X10 has the 802.11s feature enabled if I can't put a single other AP in the house that supports it without it being on a different network.

I am sure I am missing something, so please clue me in on what it is. I would think with $800+ invested in these R9000s I should be able to have my mobile devices move from one side of the house to the other, leveraging the stronger of the two signals, without dropping or hanging on to the other AP until the signal drops below -74db.  HELP!   Mesh is of no real value to me, as I have ethernet everywhere. There has to be a solution!

Appears there are various misunderstandings on standards and features and what you do need or want.

What is sold on the market as Mesh systems are throw-in solutions by plugging some boxes to power and get things running over the wireless backhaul. Most Mesh systems are using proprietary schemes supported by STP, some are using 802.11s which does nothing but handling the wireless mesh between multiple wireless boxes. What makes devices seamlessly roaming are essentially 802.11k, 802.11v, 802.11r which is implemented on these Mesh systems as required for simple home or throw in SOHO or very small business networks.

I don't know what you have expected, what the plan is, why and how the Orbi Pro WiFi 6 does cause issues with whatever existing network, or why any undefined LAG does fail apart (look, I have ideas - or probably even know). This Orbi Pro WiFi 6 system does come with a bunch of preconfigured VLANs - and when you hook this up with a whatever managed network with existing VLAN configs, STP/RSTP/MST whatever - issues are predictable.

Believe me, I don't going to break a fight for Orbi Pro WiFi 6 - mainly due to lack of information from your side. What I see is a new development - up to a year or two we often heart from community members they have bought three new routers becasue it was sold to me to make my wireless coverage better, and the marketing was soooo darned promising. 

If you want the similar functionality as you buy for a lot of $$$$$ from Cisco APs or $$$$ Cisco Meraki AP and even much more annual $$$/$$$$ for everything - yes, Netgear has a lot of this available for some $$$ and $$ per year. Look into the Netgear Insight system, get at least some APs to start based on the needs of the location (some simple WAC505 can do a fine job in your garage, hobby room, some WAC540 where you need more client coverage or intend to link up some wireless connected WAC564, or WAX610 indoor or WAX610X for the garden), depending on the wiring a central or some distributed PoE+ switches. If your existing network is mostly wired anyway, if you want to extend the network and wireless coverage adding some access points, with your apparent knowledge from work, I'm not convinced any Orbi [Pro] [WiFi 6] whatever variant is right for your home. Because for the experience you have at your business there is no need for Orbi at all.  

If you have some newer Netgear Smart Managed Pro switches, they might have become cloud manageable already, too.

Back to the drawing board. Define what you have. Define what you need.

Scratch the idea of the R9000 - unless you can keep it rattling as a simple NAT router with WiFi disabled (or handling Mesh-ignorant Internet of Junk devices on a dedicated Wireless SSID, probably also retaining the seciond R9000 in AP mode for the same purpose) instead of a provider CPE you might need for IPTV and fixed network VoIP anyway.

Edit: Then please add a list of 2.4 GHz devices you failed to add - and try to explain why. There is no reason a 2.4 GHz device does not connect to the Orbi - except it's non-maintained junk not aware of the additional bits in the standards compliant WiFi 6 and the radio resource managent.  And try to understand single SSID spanning all bands is essential for coverage. Explained all this to many times - and I won't do it again here.