I know this post is a few months old, but FWIW I just bought a used but mint 2021 tegimented U1 on a Sinn owners group on Facebook. There are definitely scammers on Facebook watch B/S/T groups but there are ways to conduct due diligence. Under $2k with both bracelet and rubber strap (which I like more than I expected to).
IMG_3022 by Palmguy, on Flickr
It's kind of a shame that the Sinn is going to be relegated to not being worn particularly often, but the Apple Watch is heavily engrained into my daily life right now. I've had several other watches to fill this particular void for me (mostly something I can wear on the occasions that I can't wear a smart watch at work) but I've always looked at them and wished they were a U1. Came across this one used and had to jump on it.
I still have a "regular" Apple Watch (series 7 black titanium) but haven't worn it in months. I wish the Ultra came in black but it's compelling enough that's it's just what I wear every day now. The battery can go two days if necessary where the standard AW is usually running dry at or before the end of one day.
IMG_3023 by Palmguy, on Flickr