@Tripilla 

Hi, clearly, they have no intention to support manually changing the channels at least in the next couple months, even a few years. But I would like to point out when I said I should have the freedom to change the channel of router, yes, It is right. but it is just considered a feature request and they don’t have to implement all my required features, otherwise there wouldn’t be so much complaints.While if I said to them I had a problem (maybe it is caused by the channel or not) and ask for support, then they have to find a solution, or at least a workaround for me(a beta firmware or even a different model, It depends.) since TP-Link has promised their technical service. 

BTW, I guess that’s why the moderator kept asking to provide the reasons/ details of your problem, sending emails. So instead of waitting for them changing their mind, why don't try their suggestions to ask for support.

@TP-Link 

First of all, thank you for the fast reply, seems like you at least take our problems serious here. For your question, there seem to be more brands with problems related to dropouts using different Deco setups. It seems to be more common for Xiaomi divices tho, ive also seen this behaviour for Oneplus devices and also some others bin smartphone devices of various brands. It even doesn't completely drop out most of the time but when changing to a different accesspoint it shows up as connected to the WiFi in the first glance but after like 10 minutes it shows up like if the WiFi got no working connection to the internet. Which 100% is not the case as others devices in the WiFi/Lan got perfectly find connection at the same time. The worst thing is, that when walking around in the WiFi covered area it sometimes looks like your perfectly fine switching to accesspoints as needed and If you drop out "officially" at a way later time you sometimes get messages received like 1-2 hours ago, they simply didn't arrive before dropping as uut of the WiFi as the devices think they are connected to the WiFi properly while in reality they lost connection after switching APs long ago. I tried various different settings for the decos and the devices at different locations. getting the same results. Sometimes more often, sometimes less often, even for the same device after repeating the exact same path to swap to the same accesspoints - the result varies. It really seems to have something to so with channels and/or channelwidths. Any advice will be appretiated, if you don't think this is related to Channels. I am pretty sure i tried all different settings available in the devices, as well as the decos allready - along with testing different types of decos as well as mixed setups using different bauckhaul methods as well, just for testing purposes. The only thing i could't try yet is changing the channels as Deco seems to always pick the most crowded or at least overlapping it by a huge chunk  they even seem to be oddly accurate at perfo4ming this "task". This Just doesn't seem Like working as intended - given the fact, that there is even a tool to check for interferences.