Could I potentially cure sudden alchohol intolerance?

It has come to my attention that I most likely have developed sudden onset alcohol intolerance and I’m wondering if some factors caused it and then could potentially be fixed?

I never had issues drinking in the past, didn’t matter the type of alchohol. I started drinking ~14-15 years old at parties. I never was a daily drinker and never had a problem stopping/quiting. Ex. Sometimes id have a boxing match and quit drinking for a few months before hand while cutting. So I don’t think alcoholism is a factor.

Around my mid twenties I started to wonder if I had developed an allergy because evertime I took a few sips of alcohol I would get a stuffy nose. If I drank all night for a party or something sometimes my eyes would even water. After a year or two of that I started to notice when I was drinking I wasn’t getting drunk anymore no matter how much I drank. At this point I was only going out with friends once ever few months. Maybe even only 2-3 times a year. Now today in my late 20s, I have one sip and I’m violently nauseous. If I push through and have a few drinks the next few days I am violently ill nauseous beyond belief but usually can’t actually get sick.

I started researching and realized I had clear symptoms of onset alchohol intolerance…..not that anyone believes me. I get told “everyone’s tolerance goes down when you get older” but it’s definitely more than that.

Reading through the science of it I’m concerned I may have caused this inadvertently. #1 I used to be keto (and am not diabetic) and I am wondering if this somehow fucked my system (liver, enzymes) and caused this. #2 I am at my heaviest weight ever and wondering if that had an affect and therefore….if I lost weight could I potentially fix this?