Yes, without good help at a bike shop and all the sizes available to try, it can be hard to choose.

At least we know the 50 is probably the wrong bike.

I can't really say for sure what you should do, but at least you are between two sizes. Ideally you would get good advice from someone at a bike shop and be able to try both 52 and 54.

A last thing I will note: the 52 has 10mm less reach to the handlebars, but it also has a lower front end (19mm less stack). It might put you in a more aggressive position (which for some is good, for me would be bad because I'm not that flexible). However, you can always change the position of the handlebars a bit by changing the stem.