Yeah, GHB is kind of nice in being alcohol-like without some of the worst effects. But I think the thin line between effective-dose and unconscious-dose makes it unlikely to fill this niche (remembering a Burning Man 20 years or so ago in which we inadvertently posed as Camp Jonestown Massacre after a couple dozen people took just a little too much and ended up splayed at random locations).
Thinking slightly outside the box here... seems that most of the benefits you identify could also be satisfied by a drug (e.g. valium) that has similar effects without being so freaking toxic (though I understand valium is similarly addictive, alas). Maybe we need to bring back recreational valium. Casual pop-culture reading suggests to me that back in the 70s-80s, valium & quaaludes & the like were quite the thing in party circles.
Some (actually, Much) additional nuance about empathy and its components that might add some context to this discussion at this link: https://www.lesswrong.com/posts/SMziBSCT9fiz5yG3L/notes-on-empathy
In particular, as other commenters have already pointed out, there is something about "perspective taking" (the shift from considering how you feel about what they feel to considering how they feel) that may be resulting in the OP's frustration.
VO2max
FWIW, I would find it helpful for you to define this term on first use.
A wikipedia-style short biography of a person will tell you what they did and accomplished.
A good, critical, book-length biography can help you see, in something more like real-time, what decisions the person made along the way, what constraints they were operating under, how the effects of those decisions looked as they happened (without the benefit of hindsight), and what atmospheric effects contributed to the arc of the person's life. This is much more personally applicable to you as the reader who has to live your life in real-time.
I enjoy reading biographies of people who made unusual commitments so I can imagine what that sort of pioneer work might have felt like. An extremely weird example (both in the writing style and the subject matter) that has stuck with me is Gabriella Fiori's biography of Simone Weil (Simone Weil: An Intellectual Biography). Another good one is Fiona Joseph's biography of Beatrice Cadbury (Beatrice: the Cadbury Heiress Who Gave Away Her Fortune). Sue Prideaux's I Am Dynamite! A Life of Nietzsche was everything I wanted in a Nietzsche bio.
I have just a superficial familiarity with the lit around this, and I'm wondering if what you're calling "unawareness" is the same concept as what other people have been calling "cluelessness" in this context, or if it is distinct in some way. They seem at least similar.
In any case, thanks for trying to set forth in a rigorous way this problem with the EA project.
Notes on Honesty mentions a few more, including trustworthiness/reliability/dependability/conscientiousness (being honest about your promises by following-through on them), parrhesia (a sort of super-frankness pioneered by the Cynic philosophers), reputability (earning a reputation for honesty), sincerity/earnestness/authenticity (being honest in deed, not behaving ironically or in plausibly-deniable ways), straightforwardness (communicating directly, not requiring interpretation or second-guessing).
See also Notes on Sincerity and such.
I wonder if what makes alcohol superior to pharmacologically-similar drugs like diazepam in terms of socializing and bonding has less to do with the substance and its effects and more to do with the rituals and folklore around consumption.
Partially, I think alcohol just "comes on" much more quickly, and thus the drug and its effects are more tightly-linked mentally. But all of the hocus-pocus around e.g. mixing cocktails or discussing vintages or hops varieties or what-not, and then holding the potion in your hands in its specially-shaped glass, and yada yada... that's a lot of extra magic juju being added to the spell.
Put diazepam or gabapentin or what-have-you (or, who knows?, placebo?) in some exotically-shaped vehicle and administer it in some public and unusual ritual with its own exacting connoisseurship, and maybe you get everything you need.