If you are rooted you can use AdAway from Fdroid. Otherwise an option is Netguard. Be careful, not the one you download from playstore because it has less features. Get the one in github. Netguard is an advanced firewall that you can easily set to block some ads (not all, though) when importing and setting its host file. https://github.com/M66B/NetGuard/releases
Yes, but a blocker based on a local VPN is a better solution because of 2 reasons: 1. Possible bypass of the hosts file - see here. 2. Quote: This is not necessary with VPN-based blockers.
