Find my iPhone Powered off/Battery Dead

Re: “… care to explain? …”

Sure.

As already explained, when you simply “turn off” an iPhone it’s not ALL powered off.

Numerous “always-on” functions continue to operate (e.g. the clock and calendar still run); part of this always-on power goes to the bluetooth beacon for - I believe - 24 Hrs.

At this point your phone effectively functions like an AirTag; with it’s beacon detected by other Apple devices; which then relay it’s approximate position to Apple’s FindMy servers.

Unfortunately not by any “technical means.”

Dollbaby825 wrote:

so why when i power off my iphone 12 it see iphone findable?

Likely because as opposed to the phone you suggest has a dead battery, when you power off your iPhone 12, the battery isn't dead.