No One Can Login SQL Server Instance Even Though Its Services Are Running
That seems to be a firewall issue.
Open the Windows Defender Firewall with Advanced Security applet from a client machine on the same network, connect to the server, and see if you can enable the SQL Server or or TCP port. By default the port is 1433, but it might be some other port. You can use SQL Server Configuration Manager to determine which port the server is running on.
You might need to enable Remote Management of the Server Core machine.  Connect to it via RDP, open a command-prompt, and run sconfig.  There is an option to enable remote management from there.