You should be fine. Row Owners only applies to the app where you have enabled it, so applying Row Owners on your public app will protect user data, but as long as you don’t apply Row Owners on the private admin app, you will be fine and still have access to all data.
If I recall, only the basic column data is shared on a glide table between different apps. Any computed columns are not shared, and I would assume that the Row Owners indicator is included in that data that is not shared.
I have to ask though, is your admin app a private app or still a public app that anybody can sign in to? If it’s still a public app, then I would consider having columns to mark the admins as row owners for the data. Otherwise, if it’s not protected by any row owners and not protected behind a private sign in, then the data can still be accessed by anybody that signs into an app and can get to the underlying data.