The following
list of all matches lost by Federer after having a match point in it was compiled in March 2018. At that time, the list was 19 matches long. After that he has lost to Anderson in the QF of Wimbledon last year and to Novak in F of Wimbledon this year after wasting match points. Not sure whether he lost this way in any other match (probably not) since then. If so, he has lost 21 matches after having match points.As a result, one might think Roger is a choker.
However he has won
18 matches after saving at least one match point as you can see from this list. This list was made in June 2018 and I am not sure whether he won any matches after that in this fashion (after saving a match point).
Even though 21 is larger than 18, they are kind of comparable (in the sense that one is not too big than the other) and so we can call it even. After all, you win some and you lose some. So, we can give Roger a pass without calling him a choker.
However, it appears that Roger loses more important matches (GS matches and/or matches AT QF or later stages) after wasting matchpoints, while he seems to winning less important matches after saving matching points.
So, Roger is like a Pr...…..; He chokes on big ones.