You’re almost there, just change your Where-Object statement to this:
Where-Object "UserMayChangePassword" -eq 'True'
In general, when you wrap something in quotes the shell treats it as a single string, so with your statement like this:
you’re telling the shell to find an object with a property name like
which of course doesn’t work. The property name and value have to be fed to Where-Object as separate pieces of information.
In addition, the syntax for Where-Object requires that you use the logical comparator -eq rather than the arithmetic operator = (simply put, you’re doing logic, not math).