iPhone 15 plus transfer from old iPhone has frozen part way through with apps loading or waiting. I delated a VPN app which I believe was the cause of the stoppage but cannot restart the downloading

iPhone 15. plus transfer has frozen part way through and I cannot get the transfer to recommence. I downloaded software update before starting and backed up old phone to iCloud. The transfer stopped during the process. I identified the problem as being a VPN app which I deleted from the iPhone 15. I now cannot get the transfer re started and many app are frozen as loading or waiting. Some apps have transferred and are working. I have strong wi-fi and my the apps are still working on the old iPhone. I transferred my SIM card to new iPhone 15.

should I Erase All Content and Settings on new iPhone? If so can I start the transfer again? Should I move the SIM card back to old iPhone?