I tried to install this with composer but it complains that I am running php8.1 and not a version of php7.x
Topic on Extension talk:LdapAuth
I have not tried this on newer PHP versions, but it looks to be using the PHP LDAP client by Symfony 4.1. What happens if you edit the composer.json file in the LdapAuth extension directory and find the line
"symfony/ldap": "^4.1"
and change it from 4.1 to 6.2 or what ever the latest current version of Symfony Ldap is and try it again which seems to be compatible with PHP 8.1 from what I am reading unsure how compatible it is with LdapAuth however.