Lots of lights and won't shift into gear.

It's just time to get a real capable code scanner to really do a health check on the vehicle and see what you got Brake codes whatever shouldn't take but a minute somebody with a capable scanner will have all the information fairly quickly this is really common and generally not a big issue.

 

The big warning triangle, traction control light, (!), ABS, VSC, check engine and tire pressure.

I'm pretty sure there's no code that will trigger all those and the TPMS also.
Which of these already existed prior to your most recent issue of not being able to put the car into READY/drive?

After you disconnect the 12v battery and then reconnect it, then foot on brake, the first time you press the power button pretty much every warning light comes on. Press it again and the car should clear those lights and go to READY. Does that happen?

Then, if the warning lights come back, does the car stay in READY and continue to allow you to drive?
If you then turn the car off, does the whole situation begin again the next time you try to start the car. (can't get to READY?)

If so, you have a P0AA6 going on, which is a high voltage isolation fault. It is the ONLY code that can trigger while driving, let you continue to drive, then prevent going to ready on the next startup. A good code reader will tell the tale for certain.

 

Most "generic" scantools can't talk to many of the systems on a Prius. That often includes whatever tool is used at parts stores.

Here's a thread that reviews several scantool apps and devices for a smartphone. Some are capable of scanning all systems on a Gen 2 Prius for codes and data (plus other functions). A couple can retrieve INF detail codes which can be very useful if you have a code like P0AA6.

https://priuschat.com/index.php?posts/3290690

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