I've looked various places online, and every guide to enabling developer mode gives instructions using the home button (which doesn't exist anymore). For example: https://www.smartphonetics.com/ios/how-to-enable-developer-mode-on-iphone-and-ipad-in-ios-11/
Everyone else I know who has developer mode enabled has had it enabled on their previous phones, so this hasn't been an issue.
Is there a way to enable this off the phone? If not, how can I enable this on device?