Is there any possible way to prevent an iphone from being turned off i.e a setting on the device, a management software etc?

Is there any possible way to prevent an iphone from being turned off i.e a setting on the device, a management software etc?

No.

I'm not aware of any feature like that on iOS.

Nope.

Unless you were physically remove the side button, no.

That would of course also prevent you from turning it ON, too.