I agree with this. I know dual pane glass and a few things have improved the car and I know you are looking for feedback on those things, so truly I'd say 2021 was likely the best before radar disappeared.That's a hard question for me; since mine was early car, there were things included that now cost money, though not a lot.
My 2018 has been great, minor gap things on delivery handled soon after. Free premium connectivity and since it was performance, I had free super charging which I sold back to Tesla. Turns out I prefer the original center console vs the new one though I had put a film on it to make it a more mat color.
Tesla promised the car would get better and it does seem some things have happened; range reported more (battery chemistry?) and the heat pump (though seems an issue right now).
Part of the experience is Tesla itself - I'm not sure the company is improving over time, certainly I don't feel the software experience is at all.
However, I have to say that 2018 was the best, they worked out the early bugs and provided me with a great car that I truly don't have that many complaints about. They've added features along the way with SW and nothing can take away the fun and joy I've had driving it for over 3 years.