I thoroughly enjoyed it, too!

As for your "Jedi are a myth" issue (that's as spoilery as I will get) – it actually made a lot of sense to me and I really liked it. After all, think about the original trilogy. It's pretty clear that by SW: A New Hope time, when it's only Vader (and possibly the Emperor, not sure that was common knowledge) as a Force-user, it is already at the point of being a myth.

Then along comes the return of the Jedi which is… one ex-farm boy working in a super secret military organization. Of course who knows what happened between the movies, but definitely in the movies Luke certainly wasn't a flashy sort of Jedi. For one thing – who ever witnessed him being a Jedi other than the main characters?
– Blowing up first Death Star – he was an amazing pilot and great shot
– On Hoth, he's just Commander Skywalker, a well-known rebel officer
– On Bespin, he ran around with a blaster until he met Vader
– Facing Jabba (when Bib Fortuna even was skeptical), pretty much everyone who saw him there was toast, so no eyewitnesses to the downfall of a major crime lord, just burned out wreckage and at best, rumors
– On Endor, he didn't even go all Jedi in front of the other rebel assault team. He was just that quiet guy dressed in black hanging out with the General and Princess.

(Didn't even occur to me until I went through it in my head, but that other than main characters, I'm pretty sure no one ever saw Luke being a Jedi and survived.)

So even among the rebels, Luke would be more of "that hero pilot who became that weird guy everyone tells rumors about." Outside the rebels, he's one name in the story of how the Empire collapsed.

So it's not so much that the Jedi have become a myth already, but that they have been a myth ever since their downfall. Just another story/set of rumors has been added to that myth.