Hello Rabbi, I have an important question. What is the proof of certain people meeting Eliyahu HaNavi or angels, especially when it adds much to Judaism, like the Arizal and the Beis Yosef? And how would one prove certain stories in Chazal, like R’ Yehoshua Ben Levi going to Gan Eden? Thank you Rabbi, these questions have been on my mind for a while

You are touching here a much greater question: How does one have proof of anything he hears about, if he did not see it with his own eyes??? The answer is: you believe it happened based on reliable witnesses. The more reliable the witness is, and the more witnesses you have, the more proof you have. We believe in Ma'amad Har Sinai because it was witnessed by millions of reliable witnesses who gave over the same story, father to son, generation after generation. Anything brought down in Chazal we believe, because it is the oral Torah given over by the most reliable witnesses, the greatest Torah scholars, Rebbi to student, generation after generation.