Gotcha. Try looking in the DIY forum under kettles. Every build starts with a pot, so there are plenty of opinions there.
As to specs. Every kettle I've bought was somewhat smaller than rated, maybe a little maybe a lot. You have to calculate the volume from the dimensions to know what you are getting. Maybe.
Material. If it just says stainless, skip it. If they use a standard alloy such as 304, 316, they'll be proud of it and say so.
Gauge numbers. Larger number means thinner gauge. Comparing pots, a heavier weight means thicker metal.
Handles. Poor handles can really get you hurt. Personally I like to see rivets. You can tighten a leakey rivet, but a broken spot weld, that's trouble.
Induction ready. If it says so you're probably good. If if it doesn't you might be good.
Lastly, make sure you can return it without a fight. The established home brew and restaurant suppliers are your friends here. You'll pay more, but you'll get actual customer service.
You probably want a recommendation of a specific pot. Won't do it. For the same reason I won't reccomend a used car to friend. I can't afford to lose friends over a car.