It says it was the best. Not the most alcoholic.
The “best” would imply that it was alcohol. Usually the best wine was served first - when you could still taste it. After several drinks the sensitivity of your taste buds would be dulled by the alcohol. Then you served the poorer wine - because no one would be able to tell the difference at that point.
The simple fact is that wine was alcoholic. There is no dispute among actual reputable biblical scholars about this. None. That dispute only exists among latter day recent sects who do not believe in the consumption of alcohol.