I had really bad arm / wrist issues about 10 years ago due to overuse of crappy small keyboards on laptops, etc. Mechanical keyboards (after a bunch of physical therapy / massage) have been key to keep my arms healthy.
After trying probably 10 different "ergo" keyboards, the one I landed on that has been amazing for a decade is the Kinesis Ergo Advantage2
It is split, so helps with that angle, and also has depressions where your fingers go so your hands aren't cocked back causing additional strain. It also has a couple options of the mechanical switches used. Anyone struggling with pain from typing, I'd suggest looking at it. It has a learning curve but it's worth it.
After trying probably 10 different "ergo" keyboards, the one I landed on that has been amazing for a decade is the Kinesis Ergo Advantage2
https://kinesis-ergo.com/keyboards/advantage2-keyboard/
It is split, so helps with that angle, and also has depressions where your fingers go so your hands aren't cocked back causing additional strain. It also has a couple options of the mechanical switches used. Anyone struggling with pain from typing, I'd suggest looking at it. It has a learning curve but it's worth it.