Get rid of the 'high functioning' bit. Nearly all alcoholics are high functioning. There's very few of us who made it to being homeless and selling our bodies for booze. Most alcoholics are of the work hard, play hard successful sort. Other than my husband, absolutely no one in my life would believe me if I told them I was an alcoholic. I was not falling over at parties embarrassing myself. I didn't lose my job. Or my house. I looked like I drank normally enough (because other people only saw the normal drinking). Anyway, what I'm saying is don't get hung up on that label. If drinking is pulling you under, it's a problem, whether you look high functioning to others or not.
Anyway, there are 3 things I'd say worked for me. (1) I hated the term 'sober curious' (still do, sounds really wanky!) but basically, I became sober curious. I spent a few years before I got sober, circling around sober people and looking in from the outside trying to understand how they did it, what made them so happy, what made them successful and what they did. I listened to sober podcasts, I got a AF drinks subscription box, I read quit lit, I followed sober instagram accounts. Basically, I started dipping my toe in and trying to understand how other people did this thing I couldn't get my head around.
(2) I didn't make the change until I was ready. I know there is a lot of narrative around it's just an excuse to put off stopping because you'll never be ready if you keep waiting for that magic moment when you're ready. But honestly, I think being ready was key. I was really just done. I was over it all. I was miserable. There was no 'rock bottom' per se, I was just tired. And I was faced with the fact that my drinking wasn't going to change, like I was never going to be someone who could have a glass of wine and switch to fizzy water, I was always going to be someone who drank 2-3 bottles of wine a day. So either I carried on as I was - and probably dropped dead in the not too distant future - or I made the leap and did something about it. I got through the school holidays, I cleared my work schedule, made a plan and stopped because I was ready.
(3) I found a support community. I paid to join a sober support group (I'm still a member, still pay monthly, a month of support costs the same as a box of wine I'd be buying daily - so very good value for money!). If AA resonates with you, there are lots of AA meetings out there. There are other communities though, SMART, Bee Sober, just have a search on Facebook really. I joined and I participated, basically I check in every day. And at least for the first 3 months or so, a lot of my life was about being sober, I went to bed early, I didn't go to whatever friend's BBQ if I wasn't up for it, etc. I just focussed on feeling better.