Unfortunately, the example number 4 is going to be what most people refer to. There are also many posts on the subject about this if you look. Querying posts by sub fields is a huge PITA and I’ve given up the idea and I look for ways around doing it. I posted an example of working around querying sub pages on a similar topic here https://support.advancedcustomfields.com/forums/topic/get-next-post/ and it might help you.
