i have read that the iphone 15 pro requires a WiFi 6E Router. please advise if this is true.

While the newest models do have WiFI 6E capability, they are also compatible with older Wifi standards.

The iPhone 15 Pro has Wi-Fi 6E, which is the latest and fastest Wi-Fi standard. It also has backward compatibility with older Wi-Fi standards, so you can still use it with older routers and networks.