I've had a few Tesla rentals.

My #1 tip is to order a set of key cards from Tesla for $30 (for 2). You can also buy a 3/Y fob and use it. Hertz has the card in some really annoying case instead of just giving you the card. Now I put the Hertz key on the starting location and leave it there, while using my key (which easily pairs to the Tesla) for door access. So I don't have to "start" the car with the key.

My last rental I reserved a Long Range model 3 and was given the non-LR. They have told me in the past I only need to return to the same level as they gave me so I was surprised to see a $35 charging fee. I get free charging at work but the car didn't have the adapter (which was quite annoying) so I didn't top it up. In fact I paid like $10 at a supercharger to get it back to where it started. I did a car-drop on the way out as I rent from a store, so will see what they say when I pickup my next car today. Another rental, I got it at like 30, then when I returned and then immediately rented it again (30 days), they noted the charge level I brought it back at of 95% and told me that was the new requirement.

It's sad that Hertz or Tesla can't seem to figure out how to make the experience better. Using the app for door unlocking, starting the car, starting car cooling, etc etc, is such a nice part of the Tesla experience. You'd think Tesla would want to WOW renters so they buy one. Hertz also needs to up their game on how they handle charging - it seems like no one knows and is sort of arbitrary. Then again its Hertz, what's new.