We may know there is a slight difference from before when removing Apps on iPhone 11. You should keep holding on that app icon tap and ignore the contextual pop-up menu (or choose “Rearrange apps” from that menu), then in a moment the icons will wiggle and you can delete the app as usual. You can also delete apps directly from within the App Store too now, through the Updates section, allowing you to easily uninstall apps from the same place you installed them from originally. But these are not enough to remove the app completely from your iPhone because there will be caches or private data left on your iPhone. To really remove a app from your iPhone 11 completely, two-parts works are needed.
To Transfer Contacts from iPhone to OnePlus 7T, you can also use Coolmuster Mobile Transfer. First install it on your computer, start it. Connect iPhone and OnePlus 7T to computer via usb cables or wifi. A deep scan later, all data on them will be displayed on program window, including contacts. Then you can preview and choose contacts to transfer directly.