iphone 6s, FMI on, Unknown IOS version, will SSHRD script help?

I already tried it through WSL, but everytime I try to run it it gets stuck on "Getting device info and pwning... this may take a second"

the latest version an A8 device can get is IOS 12.5.7, so I went with that with the command, I want to know if using the script will even help, and if it will, how do I fix this problem?

if it won't, what other solutions are there?