Yes, I have read all four, at least once each! That is, I have read each book all the way through once, and some of the particularly interesting chapters I have reread a few times.
Jeremias had a head start on his competitors in the NT Studies field: when he was about 9 years old, I think (I’d have to look up the exact dates) his father, who was a Lutheran pastor, was appointed chaplain or something like that to the German community in Jerusalem, which meant that young Joachim spent his formative years in what must have been at least partly a Hebrew-speaking environment.
Jeremias wrote his books in German, of course. Translations can sometimes sound stiff and artificial, but these two are both very readable.