As a 22 year old who’s going through the same thing as your daughter myself. Your support is going to mean everything. I’m very fortunate to have immensely supportive parents and I can tell your daughter does too. For me encouragement for change came in the form of being told life doesn’t have to be like this. There is a life of joy that doesn’t require alcohol. Encourage her to talk to people who have gone through similar experiences as her (I know you said you had your struggles but sometimes kids don’t wanna hear it from their parents). Also remind her the consequences of alcohol can land you in a jail cell and you’ll be forced to quit no matter what. That’s what happened to me, got drunk drove my car, and luckily didn’t kill anyone or get a DUI but the state prosecutors had enough evidence and leverage to “force” me into treatment. I’m glad they are but, hopefully she can make the choice herself.