I successfully set WDS on my Archer C5 AC1200 to bridging wifi connection from my main VDSL router (ZTE Speedport Entry 2i).

But after few days of using the Archer stop working and internet connection and routers GUI are not accessible.

How I set WDS:
On Archer I made this steps based on this procedure:
https://www.tp-link.com/cz/support/faq/825/

Steps:
1. reset of Archer via reset button.
2. setup of new 2.4 & 5Ghz networks.
3. enable WDS.
4. disable DHCP.
5. setup new IP/subnet for Archer: 192.168.1.2/255.255.255.0 (main router has 192.168.1.1/255.255.255.0).

Problem description:

When I'll make this steps the WDS connection will work.
But not for long. After few days (from 2 to 14 days) the Archer stop working properly. And this has happened many times.
During the problem LEDs are light correctly - power LED with two WIFI LEDs.
The both two (2.4 & 5 Ghz) WIFI networks are still reachable with normal signal strength but after succsessful log to them the internet is not working.
I also tried cable connection from Archer to Windows PC but internet not worked and the gateway IP was 169.... (not 192....).

As you can see. It is problem with Archer itself. It is not problem with strength of signal from main router or with main VDSL router itself.

Is there some way how to make router more stable?
Or which option in router settings could help?

Version of router:
Firmware Version:3.16.0 0.9.1 v600c.0 Build 191107 Rel.15316n Hardware Version:Archer C5 v4 00000004

That firmware is lastest available for my region: https://www.tp-link.com/cz/support/download/archer-c5-v4/

FYI:
This is the next strange thing which I found.
After I made new fresh setup of WDS on Archer then I made backup of settings to .bin file. To help myself to faster recover of all settings on Archer.
But after the Archer gets to problems, I make reset and restore settings from file but nothing will hapens. Router behaving like before reset and it gets unacesable and gateway IP is 169.... .
But maybe is this problem for next topic.