Blokada is a VPN based adblocker, but Adaway can work as a hosts file based blocker, if the phone is rooted. Hosts file based blocking uses zero cpu cycles, as it’s a feature of the network stack, it’s just a file containing list of addresses to redirect, so it should use less battery than blokada. By default on all OSes this hosts file is not editable by regular users, that’s why you need root. Wikipedia article about hosts file
Without root it works the same way as blokada, as a local VPN. I always root my phones, so I don’t have experience with that, I guess it’s similar.
But you can just try it, and if you don’t like it you can get back to blokada. Also as both of them are just VPNs, you can just switch between the two, while both are installed. Also on their website there is a good FAQ: https://adaway.org/
