Good intentions can sometimes end up with bad results.  Adding indexes boosts performance until it doesn’t. Avoid over-indexing. The difference between your application being fast, responsive, and scaling properly is often dependent on how you use indexes in the database.  MongoDB is no different, its performance (and the overall performance of your application) is heavily [&]

https://www.percona.com/blog/2021/03/22/want-mongodb-performance-you-will-need-to-add-and-remove-indexes/