The SCCM admin console is very slow to load and to use. SCCM and SQL are installed on the same Microsoft Windows 2016 server.
SCCM Version: 1902
SQL Version 2016
Solution:
Change the SQL Server Cardinality Estimation of the SCCM databese to Level 110. In order to change the CE level execute the following SQL script against your SCCM Server:
ALTER DATABASE <CM_DB>
SET COMPATIBILITY_LEVEL = 110;
GO
Source: SQL query times out or console slow on certain Configuration Manager database queries