Edge and Chrome are giving me 5 hours of battery in my Snapdragon X Elite notebook while they should 14+ hours

I've bought this HP Omnibook X14 and both chrome and edge (only thing I've been using the notebook for) is giving me 5 hours battery life, while EVERY review I've seen in the internet says 14+ hours. What could be wrong? Does Firefox performs better battery wise since it's the only browser afaik that is not chromium based? I've always have 5 browser windows and one of them has like 20 tabs, but I've set the browser on the aggressive battery saver mode (inactivates tabs, etc).