If I've said it once, I've said it a million times. A basic TEFL course is a 100 to 120 hour course with at least 6 hours of observed teaching practice. Anything less is like calling an hour course in first aid a "basic nursing qualification"
The easier the course is, the harder your first job will be
Having said that, it is more a case of dedication than intellectual strain, with the possible exception of learning grammar rules and the phonemic script. The dedication needed is also why you need classroom hours