Loud sound at start up

I recently got a 2024 Prius Limited. It's been about two weeks and I have started to notice that on a cold start I place my car in reverse and then drive to get out of my parking lot. Within 30 feet of driving out of spot I hear what I can only describe is the engine turning on (although it sounds louder than when the engine kicks in while driving. ) The sound lasts for no longer than 20 seconds. And it's the the whirling ev sound.

I'm just trying in not to figure out if this is normal.

 

Yes, this is my first Prius. I do believe it's the engine revving I'll try to post a video soon.