iOS 14 widget has a lot of restrictions. But fortunately they still support the pre-iOS 14 interactive widget.
Please follow these steps.
1. Unlock your device.
2. On iPad, please swipe to the most left tab, on iPhone, please swipe left after you are on the most left tab.
3. Tap "Edit" at the bottom of the widget list.
4. Scroll down to the bottom, then tap ""Customize" button".
5. You should see the pre-iOS 14 ATracker widget there and you can add it to the old widget tab.
Here are the screenshots.
Some user reports that they need to restart the device to see the widget there.