I have an older 6th gen Intel XPS that probably lasted 7 hours max on windows and I get 6+ on Linux. Not really noticeable to me. I should have gotten the 1080p screen instead of this 4k monstrosity and battery life would have gone up 50%. The thing is also a beast at sleeping and will go well over 2 weeks before the battery drains. Which is great because I just use it on the couch now and will open it up for a few minutes here and there before shoving it back between the cushions again.
Last year I got a 12th gen framework and battery life is disappointing under Linux. Maybe 5ish hours. I can live with that but when sleeping it still drains like 25% a day.