Today I learned: If you use #ntfy and its official server ntfy.sh for push notifications and you wonder why you're not getting any of those in time when using apps such as #Element or #Fedilab you might want to look for an alternative since there is some heavy rate limiting going on:
1) Pay for ntfy.sh: https://ntfy.sh/#pricing
2) Switch to another open instance (such as https://ntfy.adminforge.de/).
3) Host your own ntfy server https://docs.ntfy.sh/install/

Don't forget to delete your topics in ntfy and to register your apps again!

#TIL