Asus AX92u No AX?

Hello, I have a RT-AX88U, which works fine. The only thing is that WIFI coverage in some rooms of my house is bad, therefore I bought dual pack AX92U. I connected the too AX88U in an AiMESH network via Ethernet cables to the AX88U unit. No WIFI backhaul I use a Samsung Galaxy S10 and that phone is compatible with WIFI6 (IEEE 802.11ax). When my phone is connected to the AX88U unit, I see a little '6' above the WIFI logo. When I walk close to one of the AiMesh unit (AX92U), it does not show the '6' aside the WIFI logo. As I have understood it AX92U is always an ax router even if you use it in an AiMesh network. Am I wrong? Is there something I can do to 'fix' this or do I have to accept that RT-AX88U is, in fact, no ax router in an AiMESH network!