Connected, but "no internet"

My setup is:
raspberry pi, 1gb SSD
Umbrell latest version
Umbrell was installed successfully, and the BTC blockhain has been fully downloaded.
The modem/router/wifi that I have from the Telco doesn’t reach everywhere in the house, so we added TPLink Deco M4 wiFi radios. This creates its own WiFi network that we (our family) all connect to throughout the house. The base station connects via Eth cable to the router/modem.
When I plug Raspberi Pi running Umbrel it works fine. However, because that wifi network is too far from my desk, I can’t reach the Umbrel http://umbrel.local/

So I tried connecting it via Eth cable to one of the TPLink stations.
This only works partially.
I can connect to umbrel.local, and it is connected to the internet, updating the blockchain.
However, when plugged in there is no internet on that network. We can still connect to the TPlink WiFi, but get “no internet”

What can I do, to have the Umbrel, connected to the TPLink (on the same WiFi network) so I can reach it and so still have internet access?

No idea what you are trying to do, but I’m pretty sure you should be able to extend your Telco WiFi network using the Deco M4 without creating another one. Check this: