Is there a way to detect the uninstallation of my app on my iPhone?

There is a way to detect uninstallation, but it's limited and it's not like apps running on each device like Android can trigger uninstallation.It's not real time either.About a week after uninstallation, you'll find out.

If the app has Push notification enabled, the Apple Push Notification Feedback Service will provide you with device tokens that did not receive Push notification.
Use it to detect that the application has been uninstalled (or has been replaced).

So to achieve what you want to do, you also need to correlate the device token with the user so that they can understand it.

A rather simple way is to use the tracking mechanism provided by the advertising SDK.

The Advertising SDK also uses the APNS Feedback Service to detect uninstallation, but it is easier to use because you do not have to implement it yourself.

For example, the following is an uninstall measurement document provided by the Adjust ad SDK.

Similarly, you may want to look up some ad tracking SDKs.

US>Measure uninstall and reinstall
https://ja.help.adjust.com/tracking/uninstalls-reinstalls#track-uninstalls-and-reinstalls-on-ios