Router Archer A5 not responding to WiFi authentication requests after a while


I bought a 30€ TP-Link Archer A5 v6 with a MediaTek MT7628A as a replacement Router. So far it flashed fine even though it is not officially supported (v5) is.

Now it isn't the fastes Router but for this price tag it runs really well.

Unfortunately after some random delay can be 1 day or 7 days I get disconnected from WiFi and the router doesn't seem to respond to authentication requests anymore (e.g. Client Device prompts me to change Password). Restarting the WiFi interface doesn't help restarting the router does usually.

I followed the steps under and set debug level to 0/verbose debugging but when the router is in this particular state it doesn't log anything about the authentication requests or at all coming from the wifi driver when it is in this state. (also nothing in dmesg)

The only thing I am seeing on the monitor interface is (besides the probes):

"564","10.829010","8e:9c:5b:**:**:**","TP-Link_**:**:**","802.11","184","Authentication, SN=698, FN=0, Flags=........"

Unfortunately I only have this android device to test with, but it should at least give some answer to this authentication request, shouldn't it?

Is it better to avoid devices with this price tag or is this a known issue with this MediaTek Chip?