Thank you for an idea!

I explored the issue a little bit to clear up the question and came to the conclusion that most likely it's a bug in react-native-maps. To show it to you I’ve created an empty project with two pages - with and without a map. Then I enabled the performance monitor from the standard debug tools of the RN and made a video that shows how the animation slows down and what happens to the metrics.

Hope it will be useful! I really appreciate your response!