Sorry that was your first experience with a Tesla, but sounds like you did okay. You're right. a TINY bit of information would've went a LONG way. A couple of things:
There is a owner's manual (fully text searchable) on the center screen. It's also available online:
https://www.tesla.com/ownersmanual
There are also these short videos to help you get started:
https://www.tesla.com/support/videos
But all you really need is this ONE video:
https://www.tesla.com/support/videos/watch/essentials-meet-your-model-y
Adjusting the side-view mirrors and steering column is right there in the very first screen when the this the main Car Menu icon. I think you can just use voice command "Adjust mirrors" or anything similar to bring it up right away.
Required use of the key card is unfortunate because the key card is really designed to be an emergency back-up solution. If you owned the vehicle, you would have your phone-as-key, and then unlocking would be automatic when you approach the vehicle while locking would be automatic when you step away from the vehicle. There's no way around it today, but Tesla really should prioritize getting custom FW and back-end infrastructure to support rentals better. That way, it would allow non-Tesla owners to be added as guest-drivers to the vehicle. This would benefit Tesla owners who are traveling and renting as our driver profile (seating position, mirrors, HVAC, entertainment settings) are all synced to the cloud and can be recalled on the rental car. Today, they already have the feature where I can "lend" my vehicle to someone and they will have access to it with their phone app, so I don't see this being too difficult for Tesla.
The stalk has a "P" and an arrow near the tip of it like this: "
P<" so it indicates that you need to push the button in. The up and down movement of the stalk has detents. There's no time element involved. You need to move it passed the detents in the respective direction to get it to Drive or Reverse. Moving the stalk before the detents will put you in "neutral."
Nearly everything is available via voice command by just pressing the right scroll button on the steering wheel -- especially when you are trying to navigate somewhere -- just describe it like a Google search... If you're specific enough, it will just navigate there. If you're not, you'll get a list of results and you can scroll through the list and see them on the map geographically -- you can also inspect each destination and see information for each one (like a phone number) before navigating to them.
I don't know about drive mode options now. You might be right and the only option is one-pedal driving. Before, we had several options... I liked roll mode with high-regen because it can be the most efficient and really feels like a perfectly-shifted manual transmission. My new Model X only has one-pedal driving mode. I think it might be the same for the new 3 & Y. My 2018 Model 3 still has roll mode. The older cars also have a "creep" mode, which paired with low-regen will emulate an automatic transmission (with no gear shifts, obviously). That will give you that "coasting" feel... But honestly, when you're used to regen, that automatic-transmission coasting just feels like the car is out of control.
Some people take just minutes to get used to regen. Some day a few days. Within a day is about right for nearly everyone, so you're pretty typical.