I am fortunate enough to live within reasonable driving distance of a handful of dealers.
Test Drives
I was very frustrated to learn in March of 2020 that there was no program available for dealers to have any units on their lot that were not ordered. However, by April or May, two dealers had one on site on a temporary basis, and I went for a test drive then. It was really cool to give it a spin. Drove it on the highway to see how cleanly it accelerates, how it jumps from 40-60 in an effortless flash. I got to do some cornering, but no slalom-like roads where I was. We also tested the Parking Assist feature (creepy, but I like it).
Negotiation
I approached the five dealers within a reasonable drive (even defining reasonable as one that would require a stop for recharging on the way home). Most dealers said the price was not negotiable. However, as soon as one dealer was willing to give me $500 off, another dealer said they'd do $100 cheaper than any other offer. Oddly, I got an email from the sales manager at a dealer who was very flat about it being non-negotiable. I asked in reply if they wanted to win my business, he asked me to name my price. I may have posted this elsewhere, but I told him $1000 off, and they accepted. I did not go back to other dealers who had made offers, as I felt like I had to honor my request. (I know, I really could have, but I chose not to optimize entirely on price.)
I do think if you have multiple dealers you could feasibly choose, you could get at least one of them to discount you at least $500. You can just play them off each other, or, simply view each conversation as "I have another dealer whom I could work with." (The BATNA, in effect).
Oh, and you'll be ordering a 2022 now. I wouldn't expect those to drive any differently from the 2021s, though.