Disclaimer: not a doctor, etc.
The usual tenting angle (Fn row taller than space bar row) is pants-on-head stupid as it puts your wrist in an unnatural up-down angle. So the first thing to do is reverse that and have "negative tilt" with a riser under the front of the keyboard instead of those stupid rear feet.
Then you want to fix the unnatural left-right wrist angle you're in when typing on a straight keyboard. That angle pushes the pinky side of your hands outward. This is also stupid. The solution is to use two halves rather than a single keyboard and angle each so that your wrists aren't bent. Note the keyboard angle brings the fn keys on the inner edges closer together and the win/ctrl/alt/space keys in each side farther apart, just like your arms in a natural position. Imagine that!
We're making progress but there's still the issue of forearm rotation. Holding your hands mostly flat palm down in front of you requires rotating your forearm and wrist. This is also very stupid. The solution is simple: take your two halves and prop up the inner edges so your keyboard looks like a tent.
There. Now you can type without injuring the crap out of your arms and wrists for no reason at all.
tl;dr toss your keyboard, get a split, tent it, angle the halves, and make sure it slopes away from you some. Everything else will make your problem worse.
Other than buying a split keyboard, these tenting and angling tweaks don't have to cost anything. I often use scrap wood or cardboard to angle and tent.
Also, wrist rests should really be called palm rests. If you're resting your wrists on them you're going to mess yourself up.
Source: I've been dealing with keyboard-related pain daily for 20 years and have it under control due to the above methods. The alternative is literally being unable to type anything at all for days.