Is there a good replacement for Growl/Prowl?

I have several remote Raspberry Pies from which I have been sending notices to my Mac and iOS devices using a combination of Growl and Prowl. Growl is no longer supported. Beginning with Catalina, Growl crashed quite often and with Big Sur it is very unstable. I'm looking for a replacement messaging system that I can use with existing bash scripts on the remote Pies. I can use Prowl's API to send messages to the iOS devices, but not to the Mac. I can use OSASCRIPT via SSH to send messages to the Mac, but they don't make it to the iOS devices. I can use email which gets to all devices, but ends up making a very cluttered inbox. I've looked at Boxcar, but it seems to be a little much for my needs. Any ideas?