I use an external keyboard for my right hand and the laptop keyboard for my left so that the left one can be more straight. So that an inflammation doesn’t worsen. (This is on Ubuntu/Gnome 3 (ugh))
I have tried two external keyboards (on the laptop) but then I had to deal with very annoying input lag from the second plugged in keyboard.
What about using a split keyboard like those from: Kinesis[1], ZSA Moonlander[2] or ErgoDox[3] or Voyager[4], etc. Or full key keyboard with split design like seen at: Logitec[5], Microsoft and others[6].
I feel that. It seems like you've found something that works for you, but if you're ever looking to change up your setup, I've got some keyboards that are helpful to me. I'm attached to a certain pricey brand (and they're awesome and I wholeheartedly endorse them), but you can find some cheaper alternatives as well that are similar. (They're also open hardware, so you could build them if you're so inclined.)
I have a Keyboard.io Atreus. It's very small, it has 44 keys. You don't move your hands to type, they just stay where they are and only your fingers move. The downside is that, to make up for the lack of keys, you've gotta use several layers with modifier keys (eg I have 3).
I've also got a split keyboard (Keyboard.io Model 100). Each side can be positioned independently, and they're hooked together by an Ethernet chord. So you could get a similar set up to what you have now.
The other things that were important for me are a vertical mouse (Logitech MX Pro Vertical), and a gaming mousepad, and additional padding for my chair's armrests.
Obligatory reminder that everyone using a computer all day should make sure to put some effort into ergonomics and not developing an RSI.
I need to let my arm rest on a wrist patch and/or armchair. Else I get inflammation. With my second keyboard (for my Mac) I didn't do this, as it stands behind the first one, and so now I have developed an inflammation.
The advice for vertical mouse I read before. But I like that my mice are wireless (Logitech G903 and Apple Magic Mouse 2).
There are wireless vertical mice, e.g. the cherry MW 4500, cheap enough to just test it. I really like that model, it comes with a dongle (so likely better latency than if it used Bluetooth) and uses regular batteries, so it can be powered with rechargeable ones. No idea which sensor is in there, likely nothing great, but it worked fine for me for work and gaming.
Yeah that seems like great bang for the buck. I'll try that one and if it works out I will use it till it breaks [EDIT: or try one of the mentioned ones and send it back within 2 weeks if not satisfied]. I read reviews and if it works out I will go for either BakkerElkhuizen Evoluent D Wireless (probably this one), R-Go Tools: Break HE, or Logitech MX Vertical.
Trackball attains too much dirt (heck, even mice do). Maybe BakkerElkhuizen ErgoSlider Plus would also work.
The evoluent mouse often pop up in this space, quite expensive. Not sure they are worth the price. I had a different r-go mouse in for a small test, felt OK, but not better then the cherry. The Logitech MX Vertical should be the mainstream option, but Logitech has quality issues, specifically by using switches that double click after a while. For the price not okay, even if it can happen with many different mice as well.
I really liked the cherry mouse given the alternatives I had at the time ;)
Supposedly the scroll wheel gets dirty quickly, and requires cleaning with contact spray and then some lube. It also has no support for pink apparently. People are claiming defect after X months. Either way, in EU I get 2 years warranty and the price warrants trying it out.
I did never need contact spray with it, during a few years now. The pinky finger might depend on hand size :)
I did have a broken button though, claimed warranty and got the money back, afterwards I soldered in a new button. Was easy enough, but I hope it does not happen too often! https://www.onli-blogging.de/2103/Kaputten-Maustaster-auswec... was my writeup.
Useful to know: Cherry has an additional manufacturer warranty for that mouse, which I claimed with the vendor.
I have tried two external keyboards (on the laptop) but then I had to deal with very annoying input lag from the second plugged in keyboard.