Hello, This is Viikky,
i have done with the task for push notification in react native for cross platform. and i also working with firebase in react native i have created many projects that includes firebase functionalities like Auth, Firestore, Storage, Crashlytics, push notification, adMob and etc.
i have been experience of 2 years in react native i can accomplish your task as per your requirements.
Please ping me.
Thanks.