I haven’t slept last night and this is the first that came to my sleepy mind. I feel all so clever now Why isn’t this answer the obvious one? There are people here suggesting printing extensions. Playing with S as forward will be as easy as with a W if the finger is shorter and 99% of games allow you to change that, if not then you can temporarily use a mapper.
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Alternatively, I believe there are some gaming button pads too that are programable where the keys aren’t shifted horizontally from the neighboring rows. Like a Razer Tartarus for example. If you already building PCs it could be worth the investment.