I was trying to setup your plugin for the last one month and got to know that two major drawbacks are there, which your team directly said not possible to develop even.
1) If the course validity of a user expire & we can not extend the access for few more days to complete the remaining task to get the course certificate. Either you extend the course duration for all or the user needs to buy the course again, which is not practical. There should be an option at user level to change the course end date.
2) There is no option to enter the embed code directly. One typical method to include the pdf is using short code, which is not working properly. On some browsers & on my mobile it is asking me to download the file instead of embedding & displaying the content. Your team said it is my browser issue, but I can see the pdf on other sites.