In that case hydroxide-push will work too, which is good news!
Just note that the IMAP, SMTP and CardDav functions have been stripped out from this push version. If there’s interest to have those too, a different version with the push stuff added on top of full Hydroxide could be made. It will require a bit of time to develop.
The scope of hydroxide-push is only push notifications for now.
I think it does require a paid account, Hydroxide basically acts like the official Proton bridge.
I haven’t actually tested with a free account, so there’s a chance it does work. When you run the auth command (which is the same as upstream Hydroxide), it will probably throw an error.
If you have a free account and try this out (or Hydroxide), please report how it goes back here, I’ll add a note to the readme. Upstream doesn’t seem to mention this in their repo either.
In that case it’s definetly worth it to try this out, just so you have one more notification to disable