If you want to use PowerShell to configure SSL connection, check the "How to configure ApexSQL Monitor SSL web access (https) manually" KB article - https://knowledgebase.apexs....

The article is written to explain how to configure SSL connection for ApexSQL Monitor, but you just need to adapt scripts via replacing scripts’ parameters with yours

Do we have any powershell script to achieve this?

Sql configuration certificates is not reflacting changes which are done in certificate manager in windows

When the time comes to renew, will client applications get interrupted when the configured certificate on the server changes?

I configured ForceEncryption to yes and selected the certificate on SQL server.
It's still allowing the connections from clients that are not passing the valid certificate and clients that are not using encryption.
What's the point of ForcingEncryption on server if client side configuration can manipulate it ?
How do I configure the SQL server to reject those clients ?

I you select ForcingEncryption on server all clients will use encryption, no exceptions, using server certificate ether self signed or trusted if installed. You can check it with the network sniffer like Wireshark or by ruining "select * from sys.dm_exec_connections"