Thet probably have the contact tracing feature enabled - that thing eats through the battery pretty quickly.

I have contact tracing enabled on my iPhone. Charge it nightly, usually sits around 70%-80% when i plug it in again the following evening.

Then again, i've been spending most of last year in my home, and i live in a rural area, so not much activity besides my wife and kids. I can only assume that the busier your surroundings, the more power is being drawn for contact tracing.