Get your USA ATP and work on your JAA/EASA ATPL.
I believe there are 14 exams to take. It is the equivalent of two years of college.
So if you think you are good? The JAA ATPL will make you better.
What is grivation?
What is the minimum micro tesla units for a magnetic compass to operate properly?
Name the layers of the ionosphere and what altitudes are they found?
What is the maximum compass deviation allowed for a standby compass?
What is an optimum frequency for an HF radio?
I believe I heard some of the Mideast carriers like the JAA ATPL and Cathay Pacific gets a ha*don over it. At least you could do a distance learning course and get through the exams and put it on Curriculum Vitae (JAA speak for a resume).
As someone once told me, “The more you know about a subject the more you realize you didn’t know.”