@ViennaCalling 

Hello, Deco devices doesn't support to activate 2.4/5.0 by each Deco node separately. Generally, whether a device connects to the 2.4G or 5G band depends on the device itself. When a device connects to the Deco network, Deco will detect the surrounding Deco Wi-Fi signal and then recommend it connecting to a stronger Wi-Fi network. However, whether the device roams to other Wi-Fi networks or not depends on its own roaming mechanism.

If the Huawei Mediapad M5 can detect a decent 5G signal in the location where you want to connect with 5G band, try the steps below to check if you can make it connect to the 5G stably:

1. Turn off the 2.4G Wi-Fi network on the Deco app, then connect the Huawei Mediapad M5 to the 5G network.

2. Tap the Huawei Mediapad M5 on the dashboard of the Deco app, then click on the Settings icon in the upper right corner. After that, switch off the Mesh Technology option. In this case, Deco will not recommend the client device to roam to the other band.

@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 switching off 2.4ghz on particular Deco devices. It would be a great feature enhancement for the next firmware upgrade. DEVOLO is doing so! 

The wierd thing is, when I restart Wi-Fi close to an access point, it connects at 5.0ghz to the access point. When I move the tablet,  it connects to the router, which lies between two access points, at 2.4ghz. But it does not change to an access point anymore automatically, even when it's close beside. 

@ViennaCalling 

Sorry, forgot to mention that you can enable the 2.4G again after finishing the first two steps.

However, if this still doesn't help, you could wait for the new official firmware in the near future, which will optimize the network connection status.