It's probably due to kde connect using the same app id org.kde.kdeconnect_tp on both f-droid and google play listing, so play protect think your copy installed from f-droid is fake because it's not installed from google play yet have the same app id.
It happened to me today, I installed it from F-droid.
I just went ahead and disabled Play protect.
It's probably due to kde connect using the same app id
org.kde.kdeconnect_tpon both f-droid and google play listing, so play protect think your copy installed from f-droid is fake because it's not installed from google play yet have the same app id.