Hello @Roger Roger !
The impact is that any remote Powershell Operations will fail
BUT
You can filter this only to allow Internal IPs , or by server and pair of servers so you will have at one hand the Hardening , and also the operational access you may need
You can create an inbound rule that allows connections on the WinRM port (typically 5985 for HTTP and 5986 for HTTPS) but restrict the source IP addresses to your LAN's IP range. This can be done through Windows Firewall with Advanced Security
Have a look please :
I hope this helps!
Kindly mark the answer as Accepted and Upvote in case it helped!
Regards