but those are only effective as long as Google is playing nice

you are assuming the use of a chromium based browser. and then avoiding youtube and gmaps is not as hard as switching to linuxon PC. ok maybe it’s easy for me, because I don’t use youtube for entertainment and so I’m not annoyed on that level if invidious breaks down, and openstreetmap is usable in the area, but you get the idea

Though I’d say running custom rom is an exception from the rule

that in itself is not enough though. even lineage still uses google services, without opengapps. calyx, iodé, graphene strips that out, but most custom roms are not interested in that