A split keyboard is a huge win. When you sit with your hands in front of you, they don't naturally want to go in towards the center. They want to be offset a bit.
Below the desk keyboard tray -- Look up an ergonomics diagram. You aren't supposed to have your hands going up to get to your desk. It's supposed to be a 90 degree angle.
Going mechanical. I run Kailh Silvers, which are incredibly light and have a 1.1 mm travel distance before the key registers. It's like typing on air. I barely have to move my fingers. This, of course, takes some getting used to.
Going ortholinear. Staggered keys are just a remnant of old typewriters. Your fingers were built to go straight back and forth. Making them go sideways forces _a lot_ of extra wrist movement. Again, this takes some time to learn.
Curved keyboard well. Your fingers aren't all the same length. Couldn't we make something that puts all of the fingers closer to their keys in the resting position? Yes. See below.
After a little time with mechanical keyboards, I ended up just going all out and building myself a Dactyl. That's a split ortholinear keyboard with a curved keywell, and is basically as ergonomic as it gets. If you want advise on how to build one, I can help point you in the right direction. It took probably 10 hours. Otherwise the closest thing is an Ergodox or Kinesis Advantage. It only took a Sunday to get mostly used to it, and my typing speed has actually gotten way faster. I detailed the learning curve here: https://www.reddit.com/r/MechanicalKeyboards/comments/azkkpz...
The only disadvantage is that if you bring one of these into work, get ready to catch some flack :D
At this point I've got my own chair, standing desk converter, mouse and keyboard. I plan on coding for a long time, not just for the money but because I love it. So I look like a bit of a dumbass, but in 20 years I'll still be coding.