That repo is interesting. A quick ctrl+F seems to indicate that pretty much every instance of "MongoDB" is "Moving from Mongo to Postrges or DynamoDB" (there is one single entry of moving to Mongo from MySQL). Almost as if Mongo is just not a good database (or people are too eager to use it for things which it does not do well).
Making efficient use if mongodb is very difficult but if you build your app and expectations correctly you can get something very performant. For example pre-4.x listing huge collections was unexpectedly extremely slow.
Yeah Mongo is 10 years old or so at this point. This article was written in 2015 about decisions made years earlier. It's now reached maturity and stability. It's now "boring tech".
