APIs and Microservices Projects - Exercise Tracker- Project FeedBack

Hello,

I just finished the Exercise Tracker Project. I know that my code is kinda long and somehow not really fast (the FCC test didn’t go really fast when it test on my code) so I’m looking for feedback on how can I refactor my code to make it shorter or faster, but feel free to give me any kind of feedback on how I can improve.

Here is the repl.it link of the project:
https://repl.it/@tranhongquang94/boilerplate-project-exercisetracker.

Here is the project page on FCC for reference:
https://www.freecodecamp.org/learn/apis-and-microservices/apis-and-microservices-projects/exercise-tracker.

Also, you can see in my last get handlers callback, I have to insert callback into mongoose methods instead of using async/await and try/catch block like previous functions. With the latter approach, chaining queries methods depends on optional URL queries seems to be the way but somehow the chain slice method for limit query results in an error. Would be appreciate if you guys have any idea on how to solve it with async/await. You can find the ongoing code in the async-await.js file.

Thanks a lot.
Quang