Does alcohol cause weight gain even in a calorie deficit?

This has been my first 7 days without alcohol in as long as I can remember. Honestly what’s kept me motivated more than anything else is the way I am visibly shedding weight since I started.

I’m not an exceedingly heavy guy but my BMI is about 28 with about 22% body fat, so I could stand to lose a few pounds. And I’ve really been trying hard to do so — I’ve been exercising religiously and tracking my calories on a daily basis (including every drop of alcohol) for about a year, and I’ve been very frustrated with meager-at-best results. I’ll lose half a pound here, gain it back the next week, so on and so forth. Maybe I’m “recomping” but I don’t feel like I look much different.

…But one week without alcohol and I dropped 2.4 lbs. I’m aware alcohol is high in calories, but my average daily calorie intake hasn’t actually changed as I’ve more than made up for the booze with other things (I’ve become very fond of Mexican Coca Cola because of the glass bottle). And if anything I’m exercising a little less than usual… I haven’t been able to get any good sleep with these awful vivid nightmares which makes it hard to drag myself to the gym like I ordinarily would.

I’m curious to know if anyone has had a similar experience. Also, if any of y’all know anything about nutrition/biology, I want to understand what’s going on here… aside from being simply high in calories, does alcohol make it hard to lose weight even in an overall calorie deficit?