As per my project requirements I am using Flutter google map version google_maps_flutter:2.1.10,
I know in updated version this black UI is resolved(but there is crash issue https://github.com/flutter/flutter/issues/105965)
So per my application 2.1.10 version work properly,and even I minimize thus black screen UI issu by using this code,
if (defaultTargetPlatform == TargetPlatform.android) {
AndroidGoogleMapsFlutter.useAndroidViewSurface = true;
}
Basically by this code my apps 70% time black UI is not show on map loading.its work in lot of devices(Like some Samsung and MI devices) But in OPPO,VIVO devices I am still facing this issue,and even I tried a option of set map style,but nothing is work.