Okay, so in this video title I kind of lied. Technically, a map projection is not the same thing as a CRS - coordinate reference system - but that's not really important for now. What is important is understanding how to change the CRS in QGIS when you need to. It's one of many very powerful things about QGIS and it's super-simple, but can be confusing at first.
Take a look at the video to see what I mean. I've used Greenland here as it's a really good example of how using an appropriate CRS is important. They are all 'wrong' to some extent though because they are all just different ways of representing on a flat screen something that is not actually flat! But you know that already.
See my intro and intermediate QGIS courses for more: https://www.udemy.com/user/alasdair-r...