Echoing some of the sentiment, people playing music out loud need to be given one warning and then if they refuse to obey, ejected at the next stop. Headphones aren't expensive, and an adapter for USB-C is only about £5, they can do one.
Alcohol is a slightly different matter. As mentioned, it's more the idiots who get completely pissed or use it as an excuse to behave like an (insert preferred word here). I had dinner with family on Sunday, two bottles essentially between myself and my grandad, two pints at the Tap and then nothing till I got home. Some people would have been a hats without drinking on the train in that scenario, the issue is ASB and anyone commiting ASB, in any location, needs to be dealt with with the full weight of the law.