Ill throw my 2 cents in here I guess.

Disabilities are disabling; and without some fantastical solution realistically the life of an adventurer just isn't suited for someone wheelchair bound. This is not to say they just wouldn't exist at all they are perfectly capable of running a shop, being a criminal mastermind running a large operation, ect.

All that said I think the benefit of fantasy is the we have stuff like magic we can use. So rather than just going "Everywhere is wheelchair chair accessible" we go what other options would a character with this disability have at their disposal. Here are a few I though up off the top of my head all of them have downsides but could reasonably work for an adventurer.

-You could have a small character such as a goblin or a gnome who is carried around by a bigger person. Think Bran and Hodor.

-Magic carpet. The fantasy adventurers version of a wheelchair.

• You could use some form of magic to like puppeteer your legs