There's a lot of holes in the information provided such as where you are signed into these devices. Is your Apple the account the main one, or is it only entered in Media & Purchases? What exactly you need to do will depend upon where you signed in. To save us a lot of unnecessary work describing all the things it would help if we knew that now.
Typically when you sign out on a device the apps will remain, but they will not update and you cannot re-download them under another account. In addition, some data that is tied to a specific account may be lost.
Why on earth did you sign into the devices if you were using Family Sharing??? Family Sharing is designed so that each member signs into their own device and can download purchases and use subscriptions belonging to other family members.
What is Family Sharing? - https://support.apple.com/HT201060 - "With Family Sharing, you and up to five other family members can share access to amazing Apple services..."
This document provides a good outline of the feature:
https://support.apple.com/guide/personal-safety/manage-family-sharing-settings-ips75b3b794f/web
How to share purchases with your family - https://support.apple.com/108774
- "When you turn on purchase sharing, everyone in your family gets access to apps, music, movies, TV shows, and books that family members buy. The family organizer is billed for family members' purchases" (but read the document for the link to "learn how purchases are billed if a family member has Apple ID balance").