The system configuration comes into play, as will the settings and what you're running.

If the system has an RTX 2000 or 3500 GPU and that's in use, 2.5-3 hours is entirely reasonable.  

If the system has only Intel graphics (or you disable the nVidia GPU) the runtimes should (or will) be far longer.

The higher-end nVidia GPUs draw 115W at full speed -- and even with reduced GPU speeds, an 83 or 93 WHr battery isn't going to run for hours.  Couple it with a high resolution display and a fast CPU and you'll run up against the limits of a battery inside a system designed for portability.

Hi ejn63,

I dont play with it, just working... No gaming, no video.

Is there a way to disable the nVidia card ?

Just need autonomy. 

Just switch to integrated graphics in nVidia control panel and reboot, but battery is at 84% and annouced an autonomy of 1h20...

Will see.

So, this 7680 is awful... Battery just 2 years old, nVidia card desactivated, shadow mode in W11 25H2 (fresh install), last bios and drivers : In 1 hour battery run from 100 to 0%. Just working, no 4k/8k video, no 3D games, whatever...

A way to return this piece of <profanity removed> and get a true notebook with a decent autonomy ?

You would need to sell it for what you can get, and order a replacement more to your liking.

Dell just says buy a new battery... lol
Oh yes you have a 3 years pro support (this is not a personal computer) but you dont have the extended battery support... 
Poor professional services.

Dell does offer a separate battery service warranty - apparently your purchasing group did not opt for that. Since a battery replacement service costs about $120, it's essentially pre-purchasing a battery -- the cost of a battery is about that much.

https://www.parts-people.com/index.php?action=category&id=142&subid=1665&refine=battery