Hello! I also have Ehlers-Danlos syndrome hypermobility type (aka hypermobility syndrome) so I should be able to give you a fairly accurate answer

Personally I use a Datahand for typing (and I'm using it to write this!). Yes, they are incredibly expensive - and Datahand don't have any for sale at the moment - but you won't find a more comfortable keyboard. The keys are incredibly low-force (~10g) and arranged in a very comfy format that lets you rest your hands on the squidgy rubber pads in between keystrokes. This takes all the strain off your wrists - you'll find it difficult to find a conventional keyboard that lets you do this because the basic design underlying them all is so horrible. The key layout takes a little getting used to, took me 2-3 months to get back up to near my old speed of 50+ wpm but I can keep this up all day every day without making my hand pain any worse. I have had a lot of reconstructive surgery to the tendons in my hands so they are very sensitive to holding an ergonomically incorrect position, but I can only describe the Datahand's levels of comfort as magical. It's been my main keyboard for nearly 5 years now and I can't imagine working without it. On a standard flat keyboard I'm in pain within 5 minutes.
I would say the Kinesis Advantage and Maltron keyboards (with Cherry MX reds) are the most sensible alternatives if you can't find / afford a Datahand. Whatever you do don't get a Goldtouch, they're awful!
You could use a Datahand for gaming (with only the left hand, obviously) but you would need some key remapping. WASD would be very uncomfortable to use, I would probably use something like RDFS. Alternatively you could try a Belkin Nostromo n52 just for games:

They're cheap as chips so you could just grab one off eBay and see if you like it

I also use an Evoluent VerticalMouse and a Griffin Powermate configured as a scroll wheel - the most important thing is to make sure you try different devices until you find something that you find comfortable! If you need a new keyboard for work you may be able to get help from Access to Work (
link) - they paid for my Datahand so I was obviously very happy with them!
Hope that helps

Stone