Hi Graham,
There's nothing more devastating than the than the feeling of isolation that comes with feeling socially excluded, or that you are failing at this and being painfully aware of your deficits.

Alcohol is a crutch that effectively masks that pain before it itself exasperates any basic resources that at least help us to basically, function but yes functioning without being accepted, understood or loved for who we are is not enough to make living feel like its worthwhile.
I would think you need to take time to consider how to evaluate the deficits in your life, you feel more clearly and stop blaming yourself for your inadequacy - which you seem to be hyperfocused on and is keeping you stuck. Everyone has inadequacies it's just with ASD, the social and emotional needs are a million times more difficult to resolve because so called 'normal functioning society' doesn't validate the needs of the diversity of human experience - as you are probably painfully aware of.
The good news is that you are not alone in your predicament but it is a matter of navigating yourself toward facets of life that will support you.
Stop comparing yourself to others - this is pointless as you will never measure in equality, and why would you want to - many people who have met standard norms are not happy with their lives - so this is a pointless endeavour.
Work from where you are ATM, if you are suffering suicidally, their is only a way up and out of that, you just have to realise that you are stuck - which you have- and although this is the worst feeling/state this is the leverage you need to find a way out of that pain.
Endeavour to distance yourself from the perception of alcohol as a relationship/emotional substitute, it mimics its effects but keep being cogniscent of how it is disabling you from facing the pain of offering yourself some compassion.
Compassion isn't pity, it offers a real and fair perspective toward keeping you fighting and strong. You need to start making choices about what you need.
Posting here is a good idea as so many can identify and it just shows how you are not alone in this.
It seems like you've achieved so much, academically etc but maybe now is the time to start growing other areas to maintain yourself, the simpler things that are most important like, working on yourself, reaching out for people who can understand what it's like to be human, to struggle - this is part of living.
I hope you are doing ok?