Aftermarket head unit for 2017 four trim with JBL premium

I am looking into replacing the stock head unit in my 2017 Prius four. It has the premium JBL audio with integrated nav.

I am interested in switching that out with a head unit that has Apple CarPlay. I want to keep steering wheel controls and to be able to use the backup camera that is currently in my car. Since I will be using Waze to navigate, I don’t care if the stock nav system can still be used.

My main question is is there an existing wiring harness that I can use to still use the stock JBL speakers in my car? Also, if there isn’t an existing wiring harness, would I be able to splice the wires from my car to a new head unit? I know I’ll probably need to get a kit so I can still use the steering wheel controls. I’ve checked with Crutchfield’s website for wiring harnesses, but since I have the JBL package, they don’t carry a wiring harness that work, at least off the shelf.

Is there anything else I need to know about swapping out the stock head unit that I’ve not mentioned here? Also, if you’ve done this, is there something you wish that you would’ve known beforehand?

Thank you!