Confirmed newest TKL 17 uses yescrypt - check /etc/pam.d/common-password
It can be changed back to SHA512 simply by changing that file where it says yescrypt to SHA512 (or, I think, change for a single user by using chpasswd -c SHA512 ). Looking into using PAM and yescrypt.
I would suggest doing that as there is no library that I could find that would allow easy hashing at this point in time.
Update your password if you change that setting.