AD uses 2 types of data to represent time in attributes:
Type 1: stored as long integer, LastLogonTimeStamp, pwdLastSet falls under this category
Convert the value you want to use to long integer.
$longIntTimeValue=(Get-Date).AddDays(-60).ToFileTimeUtc()
$ldapfilter="(lastLogonTimeStamp<=$longIntTimeValue)"
Type 2: store as LDAP date type. For example, whenCreated/whenChanged. Use below filter to query
YYYY MM DD HH mm ss.s Z
Where Z signals end of the value and is mandatory
example
(whenCreated>=20221130000000.0Z)
To make a ldap filter in powershell from datetime object
$date.ToString("yyyyMMddHHmmss") + ".0Z"