So I finally came across a proprietary app that has broken notification support on my degoogled phone and there don't seem to be any alternative ways (like what Telegram FOSS or Signal do) to get it working. I tried a solution called ntfy but it didn't work. So is there a way to get it working now (preferably without utilizing Firebase because Google can read it all you know)?
I expected this question. My answer is "sorry can't tell because privacy."
Sorry can't help because insufficient data for meaningful response
This is a very meta answer to give 😄
Short answer I think you may be out of luck. Firebase/MicroG, websocket (must be included as a part of the app itself by the developer) or some NTFY workaround are really the only options that I'm aware of at this point.
Sad but thanks for the answer.