@TP-Link thank you for the answer. I tried to shut off 2.4ghz and this works. But because I'm also running 2.4ghz-only devices on one Deco device, I can't do that permanently. That's why I asked for...

I have a network of 3 Deco M4, one configured as router. My Huawei Mediapad M5 prefers to connect to the router at 2.4ghz, even when it's closer to one of the other access points. Mesh is activated...