My timeline is actually very similar to yours for the v3 roof (we were close to moving forward with v2 before Tesla decided to stop those) - 10/2019 contract, work started 2/28/2020, PTO in July.... The issues I am talking about with it not being "a good setup as a customer" is being asked to make a deposit before really getting some basic information. Some of this might be found in parts of the website, but overall it feels like the deposit is required: before you can confirm Tesla services your area (and while it may be accurate that they won't take a deposit any longer if they don't service the area, it is not obvious or historically always true); before you can get general information on when an install might occur; before you can discuss general concepts of what is practical/possible.
As a customer, I would expect to be able to get some of this general information for a large project before making a deposit. And, for other major home renovations, this is typically reasonable. (Though, as with everything at that stage, you have to be aware that the answers will tend towards sooner/easier/cheaper than reality.) Obviously, a contractor isn't going to spend a ton of time if/until they think you are serious, but answering general questions and providing a free estimate is pretty typical, and Tesla doesn't really do that. (The estimators they have give you some idea, but it is not going to be as accurate as somebody doing an on-site visit.)
Like I said before, I understand why Tesla can get away with it, and we put down a deposit expecting to wait years, so it certainly worked for them, but I don't think it is customer-friently.