This doesn't help. Windows "ping" deals with ipv6 addresses just fine. It's the multicast part that seems to be the issue. If you try `ping ff02--1s20.ipv6-literal.net` (assuming your network interface is 20), the reply says that it's pinging ff02::1%20.
Windows has "ipv6-literal.net" as a helper. It's particularly useful if you're trying to smuggle link local addresses into a UNC path:
https://ipv6-literal.com/?ipv6=fe80%3A%3A3%251