It's hard to say what will help each individual because everybody has different ergonomic needs, and obviously, nobody here can provide medical or occupational health advice.

That being said, some things to think about:

• If you haven't already, make sure that your desk height and typing style are reasonably ergonomic. Conventional wisdom is that you want your forearms to be about level with the floor and your hands should be floating above the keyboard, not resting on your desk.
• For issues that are caused by wrist angle, there are two major features a keyboard can offer:
  • Split, letting you separate the halves so that your wrists aren't pointing inward
  • Tented, meaning that you can change the angle of the keyboard so that you can get the most comfortable position rotationally
• Many ergonomic keyboards also use a column-staggered layout, which should be better for your fingers, but will require some learning curve to get used to
• Some also have keywell designs that are scooped so your fingers don't have to stretch as far

You may want to compare different layouts before deciding on a board to try: https://compare.splitkb.com/

For off the shelf prebuilts, see things like Kinesis, Keyboardio, the Glove80, Ergodox, Moonlander

For something a bit more DIY, Keebio offers a range of split boards, and some of them are available prebuilt in addition to kit form. Some are hotswap as well. Splitkb also makes really good kits.

There are lots of other vendors, like Little Keyboards, Beekeeb, Falbatech, BastardKB, ohkeycaps, and others