Just bought a 2022 -- need some advice with remote start & navigation options

I recently had to say goodbye to my 2014 Prius and hello to a 2022 Prius Prime. I understand a few things have changed and I'm having trouble figuring out what exactly my options are.

First of all, onboard navigation. I need an offline/non-phone option, but I really don't want to pay a subscription for something that used to come with the car. I'm planning to buy one of those GPS units people used to use (Garmin or similar) but it would be great to know in advance if any of them are able to use the car's built-in display. I'd also like to know if there's a way to get my phone to display maps on the screen just through Bluetooth rather than plugging it in.

Second, remote start. I'm getting mixed answers online. It seems like remote start through the app is different from remote start with a key fob? The dealership sold me a key fob and they claimed to have confirmed that remote start worked in their pre-sale inspection, but the salesman couldn't get it to work on the lot. Do I need a subscription for this one too? Or am I just pressing the buttons wrong on the fob?

I'm really liking the car so far but solving these issues would make it perfect.