iphone not showing up on th microsoft itunes app

Try iOS device not showing in iTunes for Windows - Apple Community. I would not advise switching to Devices when you want to restore an existing iTunes backup. Once you install any of Apple Music/Devices/TV iTunes is hobbled and will only manage audiobooks and podcasts. All device management features, such as restore, are suppressed.

I don't know for sure whether Devices uses the same backup location as iTunes. The traditional installer and the Microsoft Store versions of iTunes have different locations, although if needed you can move the backup data from one path to the other. I've yet to find out exactly where Devices stores backups. Music is such a poor substitute for iTunes that every time I've installed it for testing I've removed it again almost immediately.

tt2

I would suggest you install the Apple Devices App from the Microsoft Store instead of iTunes. The new app is more reliable and has started to phase out iTunes.