i was able to create an app-only sharepoint (version 2019 on premise) by following this guide https://docs.microsoft.com/en-us/sharepoint/dev/solution-guidance/security-apponly-azureacs .
I don't find any powershell command to connect to the site using the sharepoint app-only created.
I find only powershell command for sharepoint online.
Could you kindly help me? Best regards