Hey there,
I am using a TP-Link Deco BE65-5G for my apartment, along with an X50-5G to extend the mesh network (via LAN) where the BE65-5G's coverage is insufficient.

Yesterday, I noticed that while everything works fine in the office (connected via the X50-5G), I lose access to apps like Instagram, YouTube etc. when I am in the bedroom or living room (connected via the BE65-5G).

After a lot of troubleshooting, I realized the issue must be related to the DNS server. The BE65-5G uses the default DNS provided by Telekom, assigned by the SIM.

However, since the Deco X50-5G is connected via LAN and I have configured the Cloudflare DNS server (1.1.1.1 primary, 1.0.0.1 backup) in the DHCP settings, everything works smoothly once my mobile device automatically connects to it's mesh when nearby.

I am aware that I can manually change the DNS server on individual devices, but this is not always simple to implement on every device and is quite tedious, especially since we often have visitors and I don't want to change settings on their devices every time.

Using a router VPN is also not an option as I don't want to compromise on speed since there is ALSO no WireGuard VPN Protocol available in Settings (at least here in Europe).
I don't really get why there's no option yet to change the DNS in 4G/5G Mode on a $600+ router.
So please consider adding this feature soon since I don't want to rely on adding more hardware to my 1k deco setup just to have a usable connection.