What mobile OS do you use that allows an app to maintain a persistent TCP connection forever? Honest question. Last I checked, even Lineage/Graphene/etc will kill a background app after some amount of time. Doesn't matter if it's an hour or three days; if it ever happens, that's a deal breaker.
I think the right solution is to use a different notification service, not controlled by Google or Apple, not to get rid of the concept altogether.
I've not had any issues with my Samsung Android killing the Conversations client. It does have a persistent notification which is probably needed for this.
I think the right solution is to use a different notification service, not controlled by Google or Apple, not to get rid of the concept altogether.