I spend all day at a keyboard. I've never had carpal tunnel, but many years ago, became interested in ergonomics. I bought some no name ergonomic keyboard that was similar to the microsoft natural but the front of the keyboard had legs instead of the back which made more sense to me. I used that at home. Then I decided that I wanted ergo keyboards at work (2 computers) so I bought 2 microsoft naturals for work. I think I paid $5 each for them. I liked all of my ergo keyboards.
I used to peruse the Fentek site as they had many, many ergo options including some really odd ones -
https://www.fentek-ind.com/ergo.htm. The ergo boom which is what that time must have been seems to have settled to a more stable plateau of offerings. I use (and have been for ~15 years, I think) one of the odder ergo keyboards out there. I used to have 2, one that I kept at work and one that I kept at home. These days, I just carry one back and forth since I don't have a set desk at work and I'm not in the office 5 days.
The keyboard that I use is the Kinesis Ergo Advantage keyboard. It's got mechanical switches. I eventually bought a new one with the "quiet" keys although it is possible to turn on a key-click sound if you want. I swapped to quiet keys because the keyboard noise was coming across loudly on conference calls.
Kinesis makes a new and improved version of the advantage, and when they first came out you could special order them with any keyswitch you wanted out of a selection of up around 100 different switches IIRC. The kinesis-ergo company has now started selling 2 versions, one with quiet switches and one that's not quiet. But you can still go to "Upgrade keyboards" and order the Advantage 360 (or the older Advantage 2 like I have) with pretty much any key switch you want.
Upgrade
https://upgradekeyboards.com/collections/kinesis-advantage360-keyboards
kinesis ergo
https://kinesis-ergo.com/keyboards/advantage360/
Advantage (old version that I have)
Advantage 360 (the new version)
comparison between the 2
I think I paid about $260 for my first Kinesis (refurbished). I think I paid about $350-380 for my second because it was the pro version with more memory and came with a foot switch. I think my third which was a newer version was about $400. It looks like they have refurbished versions of the 2 new keyboards available now (Advantage 360 and 360 Pro)