Hi ,
I have a SCCM server which was 2012 and updated to version 1906. Now I want to uninstall the primary site completely. As we are going to have completely fresh installation.
unfortunately when I try to remove it from Add/Remove Apps in Control Panel it say :

If I want to try the main installation wizard from SCCM version 1902 iso file I get this error :

and if I try continue :

so as you can see Next button is grayed out.
I couldn`t find any proper way for Un-installation , if there is any tool for that please let me know. My main concern is removing SCCM agent properly from servers and workstations and the most important one from Active Directory. So I don`t want to try
manual removal of registry or file ,folders...