I don't know how "Jess Franco" makes a short list of bingeable directors in the first place. Even in the cult of Euro-erotic horror, I'm not sure how his name got above Bava, (early) Fulci, Rollins, Kumel, Aranda, Ercoli, etc.
The question I'm waiting for is which films qualify as Franco's "best" or (god forbid) "worst"? But it seems like a pretty rando choice either way.
With the caveat that I am nowhere near a Franco expert, I enjoyed these enough to contemplate returning to them at some point:
Vampyros Lesbos
She Killed in Ecstasy
The Devil Came from Akasava
Succubus
The Diabolical Dr. Z
Female Vampire
What a Honeymoon (*points to avatar*)
I know you've seen Count Dracula, which you seem to be fonder of than me. And I understand Bloody Moon is considered one of his sturdier works, but I didn't gel to it at all when I watched it a few years ago. Perhaps it may work better for you. At the very least there's a POV shot through a Mickey Mouse mask.
What makes Franco stand out in relation to those other directors, for better or worse, is probably the sheer volume of output. I watched an interview where one of his regulars (Paul Muller, if I remember correctly) says that he would often start thinking up his next project before he finished the one he was on, and as a result would lose interest in his current film. With that in mind, I've found the better ones to be where the leading lady is his wife/girlfriend (so Soledad Miranda or Lina Romay as the protagonist), as he seems to pay enough attention to give the movie some kind of shape or grounding. Whether or not he was a total incompetent probably needs further exploration to verify (and I confess I lack the stamina to do so comprehensively), but his '60s films that I've seen do feel sturdier, and with What a Honeymoon he shows a certain self awareness of the halfassed quality resulting from his production methods. (I found the movie quite enjoyable in its laidback way, but it helps if one is not immune to the charms of Lina Romay, especially in a cute hat. *points to avatar*)
I understand Stephen Thrower attempted such a feat with his mammoth pair of books on Franco's career. I have not read them, but judging by Nightmare USA (which I'm going through right now), I suspect they're worthwhile reading. The Important Cinema Club podcast used those books as a guide for their own neophytic Franco exploration, and do make some interesting points along the way. (I like this podcast quite a bit and listen to them regularly, although they're much better when talking about cult cinema, which they're clearly passionate about, than when they tackle more mainstream figures. Their Ray Dennis Steckler episode is one of their best. Their Robin Williams episode is one of their worst.)
https://soundcloud.com/the-important...-franco-part-1
https://soundcloud.com/the-important...-franco-part-2