Hi David, I can imagine how frustrating this must be you have a stable internet connection yet Windows keeps insisting youre offline.
To fix error 0x800704cf. reset your network stack with netsh commands then disable any proxy/VPN and enable the Microsoft Account Signin Assistant service and reset your network profile then set your DNS to 8.8.8.8, reregister Microsoft Store in PowerShell and then sign out and back into your account.
Did this error appear only in Microsoft Store or also when signing into other Microsoft apps Outlook or OneDrive?
Best regards
Lucky