As someone who first had carpal tunnel symptoms at the age of eight I have spent a fair amount of time on this problem.
Check the temperature of your working environment. Cold joints can be the cause of or exacerbate various issues. Wearing gloves may help if you can’t control the climate. A personal heater can be another good option, but make sure the heat is indirect (pointed at a wall for example) to avoid other issues from prolonged exposure.
I use a keyboard arm with negative incline positioned at a height so that my elbows are at 90° and my wrists point slightly downward. (Height of the keys relative to the wrist rest should be as close to equal as possible.) This is the opposite of what most people do with the terrible kickstands that come with keyboards. I find that the more negative incline I can get the better. My current setup allows for 20-30° Of downward wrist incline. A typical keyboard tray or palm rest will not do this, as the height from the desktop must be adjustable and it must hold the keyboard in place. Mine grips the keyboard to hold it in place.
I personally find that a trackpad is good at preventing some rsi because you can use it in a variety of positions and it forces you to stretch all of your fingers when it is below the keyboard. For my keyboard arm I designed and 3d printed a mount for an apple magic trackpd that holds it below the keyboard making it much like a laptop. This had the added benefit of keeping my fingers on home row which is more efficient.
Remapping modifiers on the keyboard is extremely helpful for reducing strain on some fingers. Things like spacemacs or ergodox which use thumbs are great. Vim keybindings help a lot too and I have almost everything vimified.
Having a large (40”+ for 4k) monitor prevents you from leaning in to read small text or “hunching over” the keyboard. (poor elbow and back alignment) The same can be done by using a larger font or lower resolution at the cost of more keystrokes for navigating long files or between apps.
Taking breaks and changing positions frequently helps of corse. (Use a sit stand desk, try kneeling on a soft mat occasionally if your desk goes low enough.)
Drink a lot of water. Hydration helps almost any bodily issue to some extent and I find that my productivity is significantly impacted by dehydration and greatly increased when I drink a lot. Soda is fine but offset the dehydration from it with extra water. This has the added benefit of forcing you to take breaks.