One solution is to use a single central maintenance and monitor database that is then added to an Availability Group for high availability.
The collected data just needs the full SQL Server instance name added, so it can be identified.

I have also seen a combined solution where the data is first stored locally and then copied into a central database.
When the central database cannot be reached, the maintenance and monitor information is not lost, just resent later.

Perhaps you can use this if it means less modification to your current maintenance and monitor system.
Use the local database for urgent alerts and the central database for less urgent reporting.