I’m assuming that each quotes post will have a number of pre-jobs posts selected under the linked_pre_job relationship field.
So in order to make the connection from the quotes post, you’ll need to search through those fields in each of the pre-jobs posts to make a match with your current quotes post. You’re essentially reversing how things typically work, you’d probably call this a reverse relationship query.
If I’ve interpreted the question correctly, it looks like someone has done exactly this on this question:
https://support.advancedcustomfields.com/forums/topic/reverse-relationship-query/
Good luck, I hope I’ve helped.
