After upgrading the collapsed topics format (We upgraded from Moodle 3.8 to Moodle 3.10) we noticed extremely slow performance on numerous courses that were using this course format.  

It appears to be related to the course_participant_count function when the option:
 
Show additional information for: assignments, quizzes, choices, feedbacks, lessons and databases in the course is set to YES.
 
Is this intended to be this computationally expensive or is there some way to optimize the information being gathered? For now we have set this option off by default and advised users not to use it unless they have a small course with a small number of users.
 
I have linked a couple of screenshots showing how much time it is sitting in this function. It takes roughly 83 seconds to just view the course (course/view.php).
 
https://photos.app.goo.gl/tikvSfzMyEyU7dku8
 
https://photos.app.goo.gl/ZmCQL3sdtiebfB7q7