When using Availability Groups with SQL Server 2019, you notice that some query slowness may occur on one or more replicas when there are CPU-intensiveSQL Server system tasks running.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
This improvement is included in the following cumulative update for SQL Server:
About cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server: