It's too complicated to setup. I gave up. My phone is de-googled so I don't get notifications for most apps. The Chinese apps always seem to get notifications. I still get my notifications when I click on the bell inside amethyst. That's good enough.
There definitely seems to be a bug related Amber, but I don't find the setup itself that complicated. Amethyst gives a nice little prompt explaining the process on first launch. FWIW, working push notifications are essential if you're trying to daily drive Amethyst DMs as a Telegram alternative.