Coming up on 3 years sober. I was typically a 1-2 drink before the set guy (although I've also used a bottle of Redbreast 12 as a snare dampener so there was some occasional deviation from that rule). It made me play a tad looser/sloppier, and since quitting my playing has become much more calculated and aware, however it has taken me the better part of 3 years to reconnect with the flow state that alcohol helped me access. I'm an ADHD kid with a touch of the 'tism which has blessed me with a hyperactive internal monologue and to this day, alcohol is the single chemical that has ever managed to quite literally flip off its switch and allow me to get connected.
I cycle month-on/month-off every psilocybe microdose regimen (1 dose every 3 days), and those sometimes land on gigs, but that's so sub-threshold that it hardly counts as a pre-gig substance. Anymore I've learned that the best thing for my body before a gig is a light easily digestible meal 2 hours before, a banana in the green room, 10-15 of a mind/puzzle game on my phone, meditation, a quick jog around the block, and then a cup of ginger tea for the stage.
I avoid getting on my soapbox about it unless the topic gets brought up like this, but quitting is the single best thing I ever did. Tour went from a stressful and exhausting monotony to a ritualistic daily routine, my sleep got better (and thus my focus), and I traded alcoholic exuberance for the borderline spiritual connection that goes with sobriety. Maybe a touch woo-woo for some, but I our instrument has a profound history of ceremonial/shamanistic use and I find that the attuned connection that goes along with sobriety makes me personally feel like I'm giving the instrument the respect it deserves.