My understanding of the many verses on the subject is that you may drink, but you shouldn’t get drunk.
Everyone’s tolerance to alcohol is different, and even one person’s tolerance is different at different times, so you aren’t going to find any absolute standard as to what “drunk” means. The Bible doesn’t focus on physical things like BAC, though, it focuses on spiritual things, so I think it’s a safe standard to say that “drunk” in the Bible means spiritually impaired. If you drink so much that it may cause you to stray spiritually, then I’d say you are drunk in the Biblical sense. If you cannot draw that line, or stop yourself from crossing it, then you probably should not drink at all.
There are also verses in the New Testament which enjoin Christians to refrain from activities which, although we may be responsible enough to engage in, would tempt others who are weaker into sin. I think alcohol falls into that category, so you probably do not want to drink with people who cannot refrain from getting drunk themselves, since you are encouraging them to sin. I think this is the reason some churches advise people to completely refrain from drinking.
At the wedding feast at Cana, did Jesus tell His mother that He was not going to contribute to the drunkeness & revelry of the evening?
Instead, He turned water into wine and the chief steward (head caterer in modern terms) called the bridegroom over and essentially chewed him out for wasting this fine wine (unknown to him miraculous) on guests who were already mostly drunk & unable to appreciate the best wine normally served first.
My teetotalling fundamentalist coworkers insist that Christ would never, ever, turn water into something that might cause scandal and that it must have been grape juice which is their definition of the Bibilical term “new wine”. Since I’m Catholic they naturally assume I’m a drunk & looking for divine excuses for the taking of strong drink.
Oh, well.