Use sp_Blitz to gather information on all servers in a centralized server/database
Brent Ozar folks already have got you 50% - Inserting sp_Blitz® Output Into a Table

My steps would be :


Log the output to a local dbastats or some dba database.
Have a list of all sql servers in your central server.
use sqlcmd and opendatasource to query remote servers and dump all the info into centralized server .. make sure you include something like collection_datetime and server_name. You can use powershell (Write-DbaDataTable) as well.
schedule above logic using sqlagent job as per your needs.
Make sure you have proper purge policy defined locally per server. I would add custom column like notified = 0 (as default) and update to 1 when you dump the data into central database. The collection_datetime and server_name will help you find out what has changed or do aggregation per server instance.