I just run AdGuard Home network wide and have never seen a huge need to run a browser blocker as well. What are you getting out of using both?
A browser-based blocker is able to block ads served by the same domain as the content you actually want, without blocking said content. They are also able to apply fixes to pages that break or have bad layouts when ads fail to load in.
UBO also blocks harmful elements inside of a page, not just page loads. I've used it to automatically remove the annoying paywalls that are just an element over the text I want to read.
AdGuard is basically pi-hole, just with different pre-configured filter lists and especially child and parental control settings. IIRC, some services can also be blocked there directly, Instagram for example.