All apps (that I know of) that do that pi-hole-style blocking will depend on utilizing the VPN-interface of Android as they use that interface to control all outgoing traffic and filter out / block blacklisted URLs.
If You already use the VPN-interface of the OS for a VPN-service You may only (or: still) use the trackers-blockers function of Advanced Privacy (feature of eOS) for blocking of trackers
(Maybe there´s options for rooted phones that do not depend on the VPN-interface of the OS)
edit: just in case you want to test an app - one example for an app that filters traffic pretty much like pi-hole does is https://blokada.org/ I use it myself and I can recommend it (Version 5, not 6) and I´d say It´s pretty much set it and forget it. It´s free but they even offer a VPN-connection as a paid service as addon/upgrade/whatever. (I am not using that service but mentioning this only to illustrate that there´s possibilities to combine the two tasks in one app/service)
(there are quite a few apps out here that do more or less the same, just slightly different approaches and options)