I currently have a server running in cloud that can send custom notification through self-hosted gotify server. The down side is battery drain, it eats more than 15% of battery per day and it's unsustainable, I have to turn on battery optimization. I know google offers GCM and FCM which instant messaging APPs uses, but I couldn't find a software that is as easily configurable and have a ready to use Android client (that preferably connects to GCM and FCM so no battery drain problem), any recommendation?