Unable to download apps on iphone 15

When I try to download an app, the payment option spins but then doesn't download, it just goes back to " get"

I have tried several online " fixes" including

• turning phone on & off
• logging out & back in
• checking wifi connection (even turned off & tried mobile data)
• credit card is linked to my apple account and I use this regularly with no issues
• address is listed in my account
• battery is fully charged
• there is no VPN associated with the account

What else could it be?????