Have not dug too deep into this other than I have sat in a few and they seem pretty darn nice/helpful.

Diawa - Relax 2 Zero 3D is one I have tried.
https://www.daiwamassage.com/collection/inversion/relax2zero3d/

Human Touch Super Novo Zero Gravity is one I have tried.  - Gen 1
https://www.humantouch.com/super-novo

What other ones have you tried/like?  I'm a little over 6 ft tall so it can't be a short chair or it won't do any good on my neck.
Reviews on these 2 units?  Good/bad/ugly
I have never gotten out of 1 of these chairs and didn't feel better.   Seems like $4,000 to $10,000 is the window.
Seems like you can relax better with a treatment at home at times, and something the entire family can use.
Thanks