‘r’ is the hardest letter to pronounce?

Haven’t watched this yet, but 6 seconds in, Damon, of Damon and Jo, says “r” is the hardest letter to pronounce in any language.

Is that true?

I kinda hope so, seeing as how both the Spanish ‘r’ and the French ‘r’ have been the bane  of my many years of non-fluency in both languages.

The other morning, coming off a Duolingo Spanish session, I rolled my r perfectly twice. It just happened. A perfect Spanish r, perfectly rolled.

Then I couldn’t do it again.