Thanks for the link to this thread
@jksmurf. I got to page four intently reading, then burned out and jumped to the end. That means I skipped 7 pages of potentially revelation level material, and my apologies for not grinding through the rest, at least not in this one sitting.
I have moved my L3 10G switch to the central com box in the closet upstairs. Buying another one was just not happening, (I did order one on Walmart bolstered by some store credit, but after a week the order self cancelled). So I have the setup (primary) router - switch - nodes. In the midst of this I was trying to help someone figure out why he could not tether his iPhone 16 to his BQ16 Pro, so I factory reset it and double NAT verified I could. If you ask me if I can get a VLAN/GN/GNP/SDN through the switch, I have my doubts. ASUS routers do not act like normal switches. EBG15 (AP mode with AiMesh) <-> GT-BE19000AI <-> L3 switch <-> nodes/unmanaged switch(es) <-> nodes. Sorry if it doesn't make sense.
The ASUS example GN setup was enlightening. I may try again to set up a single SDN. In order to get somewhat successful passthrough I had to deselect that VLAN from Tagged, but I did not add it to the Untagged. Which might be the reason it did not work for me...
I think I'll try to add that Guest Network came before Guest Network Pro, which is probably why they are limited to 2 per (1st channel in a) band, while GNP is capped at 5.
L3 switches (at least the 10 G speed kind), need fan cooling, and can be extremely loud. (Which is why I probably was able to snag this unit as used. My den is amazingly quiet again)!