You complain about URL encoding ? Enter UNC encoding ...
https://devblogs.microsoft.com/oldnewthing/20100915-00/?p=12...
> \\fe80--1ff-fe23-4567-890as3.ipv6-literal.net\share
https://devblogs.microsoft.com/oldnewthing/20100915-00/?p=12...
> \\fe80--1ff-fe23-4567-890as3.ipv6-literal.net\share