@RonMid Short answer: it is not possible. Long answer can be found here, in discussion of all TP-Link WiFi mesh offerings: TP-Link Deco Mesh vs EasyMesh vs OneMesh vs Omada Mesh What's the Difference?

@David-TP I've seen two explanations from TP-Link Support why Deco band steering logic can move device to 2.4 GHz, have found one of them here:...

@a_sh a_sh wrote @Alexandre. thanks for your answer, failed mean that all Decos become red and there is no wifi at home. Which most likely means Main Deco lost connection to the Internet. Let's...

@Zyber Main Deco must always be connected with Ethernet cable to the router.

@BruceWA You have made an assumption that in Access Point mode Deco will not work as a mesh system. This is incorrect assumption. Deco will run WiFi mesh in both Router and Access Point mode. You...

@a_sh My Deco mesh has stable Ethernet backhaul through unmanaged gigabit switches from TRENDnet and TP-Link. Three wired Deco nodes on Ethernet backhaul. No issues for about three and a half years...