Some info online from homebrewers turning theory into beer.
One guy says: I have a lot of experience brewing low carb IPA’s. I completely disagree that it is “isn’t worth the effort.” If you already homebrew, why not? There’s hardly additional effort to create a low carb beer.
Just like the folks do at the big breweries making low carb beer, your goal is to create an extremely fermentable wort, and happy yeast. Mash at 148 degrees, use a 2L yeast starter with a beast like WLP 001 (California Ale Yeast.) That’ll get you down to 1.006 FG on a good day. You’ll need an enzyme to break down the non-fermentable sugars to fermentable sugars to get it lower. I’ve used beano enzyme (the anti-fart pills). 5 crushed up pills in the fermenter at day 3. There are other options as well such as the commercial enzymes the pro’s use.
The great news is that alcohol adds body to beer - just like residual sugar adds body. So the higher the alcohol, the more body, the less RS is needed.