Will my wife lose all data etc when she finally creates her own apple id for her iPhone 13 Pro?

When iPhones first came out and before family sharing was created, the only way (at least this is what I was told) to be able to avoid having to pay for the same app for me, my wife, and my kids was to associate all devices with the same apple id. That changed several years ago and most of my family created their own apple ids and I just added them to the family so we could share data storage in icloud and not continuously get messages anytime someone changed passwords etc. Well, there was one hold out amongst the family (my wife) and I was hoping I could avoid losing data, installed apps, photos, etc when we finally create her id. I started through the process as described elsewhere in this forum and it looks like once I sign out of my apple id on her phone that she will lose nearly all of her data. Is this true? Am I missing something? I would appreciate anyone pointing me in the correct direction for the definitive answer.

Thanks.