You can give this a go but they’re quite bulky and normally quite a loose fitting, so might be hard to securely fix to your finger. I had one when I broke my thumb and it wasn’t particularly easy to play pc games with. I can’t imagine they’re that expensive though, so definitely worth a try!
I use the Razor Tartarus key pad for gaming. The keys are very easy to customize. You could potentially bind the key that is normally ‘S’ as ‘W’, then bind ‘X’ as ‘S’. If you get creative you could even use the D-Pad for some or all of your movement, then the rest of your keys could be repurposed