Hibernation kicks in automatically no matter if on or off battery. It has nothing to do with the power. You can change the settings in Power Options, Advanced Settings.  But your battery is close to end of life or already there. Replace it with a new genuine Dell from Dell. See- FAQ - Laptop battery articles - Dell Community
Hi. My name's Vamshee. I own a Dell XPS 13 7390. The performance is good, but in the last few days, the computer started to get slow and ultimately, it hibernates when opening power-intensive apps. When I turn the computer back on, it gives me a warning that 'The battery is low, please plug your computer in', when in fact the computer has been plugged in for the WHOLE time. (My battery doesn't last very long). Currently, I'm running Windows 11. So, if anybody knows what's going on, please assist me...
Dell XPS 13 7390 Hibernating Whist being plugged in!