The most common way to remove the alcohol and produce low- or no-alcohol beer is to distil normal-strength beer under a vacuum. The boiling-point is much lower under a vacuum,so the alcohol boils off without spoiling the flavour. Normal hot distillation would cook the beer.
Other methods of de-alcoholising normal beer are reverse osmosis (a kind of filtration) and spinning cone distillation (which works like a centrifuge). Reverse osmosis is expensive and probably only practical for the big breweries.
It seems to me that brewers are having much more success producing no-alcohol beer than winemakers are producing no-alcohol wine.
Before no- and low-alcohol beers became fashionable,there were some “beers” that were made entirely without fermentation. These just simulated the taste of normal beer using added flavourings and enzymes,with very limited success. You can’t really call the result beer.
It seems to me that brewers are having much more success producing no-alcohol beer than winemakers are producing no-alcohol wine. I’ve enjoyed Heaps Normal and Dainton’s New Age XPA lately;they taste pretty close to the real thing.