If I change my Apple ID will my prior purchases stay on my device?

If you change your Apple ID using the steps in this article, you will retain ownership of your prior purchases.

Note the restrictions in the article.

Apple ID Name Change

 What to do after you change your Apple ID or password - Apple Support     I suggest doing this before you change your Apple ID or password.

Yes, but you won’t be able to update them. To update them you’d have to sign back in with the AppleID used to purchase those apps. And you can only change the AppleID used in the iTunes and App stores once every 90 days.

Also note if you change the AppleID you use with iCloud, you will not be able to access your current iCloud data and iCloud email, without again signing out and signing the old AppleID back in.