I think its because there are issues in the install script, and also a lack of documentation, but would also like to know what the author thinks.
I’ve tried numerous times to start again with a new ubuntu instance, installed lamp stack to meets requirements etc, installed all PHP modules - it takes ages and is time consuming. However it comes to a griding halt on the install page. Everything else works - ie. phpMyAdmin .
I’ve just tried again, rinse and repeated - new VM - everything went ok , ubuntu 20.04.1, apache2.4.52, php7.4.33 - this time tried MariaDB - same result - all works right up to the install page because of a permission error