It's not harder than it sounds! Pi-hole is the most popular one (could it be the most individually self-hosted FLOSS service if we don't count stuff like SSH?)

It's not harder than it sounds! Pi-hole is the most popular one (could it be the most individually self-hosted FLOSS service if we don't count stuff like SSH?) but you have various options and it's not that tricky to roll your own based on dnsmasq or unbound. If you're on openwrt there are two options with Luci web-UI as well.