I suggest a good study of the Old Testament. A good way to get a real picture of that fast is learn from the Messianic movement about the feasts and the prophetic meanings of them.
However I would keep a ten foot pole between me and the "wannabee Jew" part of the movement as if you are not Jewish, you are not to be Jewish. It is good to be Goy guys. When I see a Christian wearing a Kippa it really bugs me. When the Bible says a man should pray with his head uncovered where the heck do Christians get the "lets wear a kippa cause the Jews do!" Beware the leven of the Pharasees.
Be prepared to realize that we have as much man made garbage in Christianity as the Jews have in Rabinnic Judaism. Our paths only meet in Judaism as described by the Bible. Both paths have to bend a bit to get on track.
But to know God for who he really is, is worth it. If you are really really lucky, you will find a Jewish Rabbi or Jew that is not so stuck on the traditions and more into the word and is willing to teach the Bible from a Jewish perspective. They are as rare as hens teeth but are out there. I like the Chabad pretty well, and there are a lot of independent Jews that love God with a love that will inspire you.
Judasim from a Christian perspective is a deep river that flows fast. It is a blast!
Thank you for sharing your insights, dear American in Israel. But you are quoting Quix, not me - so I’m pinging him.