Well you're going to use either your own IP address or a VPN to connect to Telegram, right? So what difference does it make if they see that you mined coins from the same address? It doesn't give away any additional info.
In retrospect, i.e. going back a month or six when you mined that crypto that you're now spending?
What nation states even have the capacity to collect (a lot of) metadata on all connections that happen anywhere on earth? They'd need to see you connecting to the VPN (easy), and they'd need to see the VPN server connecting to the mining pool server (hard unless you have access to a lot of backbones), and then correlate that data. Add additional VPN servers to make it harder as you wish.
I'm pretty sure we could narrow it down to a handful of states having the ability to get data from a lot of the web, so unless your beef is with one of them, you're pretty secure.
