In this case, we would recommend that you create applications using the Platform API. Reference the Application section in the Platform API, which we will link below.
Note that you would probably want to base all of your apps on one registered SendBird application (with one application ID). Otherwise, you would have to set up multiple plans for several applications.
Regarding push notifications on multiple devices, you can register multiple push configurations if more than one of your apps (with the same SendBird application ID) are installed on the same device. See the documentation on registering push configurations (linked below).