I run pi-hole with recursive dns so I was able to see what domains any app contacts and then I am able to lock it down on my local network no problem.

On my devices (iPhone / iPad) I also use Lockdown app which allows you to blacklist IP addresses and domain so once I can see what an app is up to using pi-hole, I manually add those domains to Lockdown so that even when I am out of the house the trackers are blocked.