Nuttso Molly supports generic messages since a few weeks. You should receive that generic message with a locked database right away. We are not aware of any problems currently. Tell us more about your setup.
I have only experienced once with delayed message that was delayed for almost 24 hour. Other than that im very pleased with it :)
My setup is: Regular Molly FCM from Github. Version: 7.0.2-1. Databse lock ON set to immediately. Uses phone lock password. Battery optimization is turned off.
What does generic message mean? It uses FCM? If so, that have been supported a while if recall correctly?