The United Nations Convention on the Rights of Persons with Disabilities defines disability as:

“long-term physical, mental, intellectual or sensory impairments which in interaction with various barriers may hinder [a person's] full and effective participation in society on an equal basis with others.”

So no. Having a dominant hand is not a disability. Most definitions agree that having a disability means being unable to perform major life activities without accommodations. Being right- or left-hand dominant isn’t a disability really by any serious definition

And frankly, what you’ve posited is a little offensive. It’s bs like this that presents barriers to getting support for people who actually do have disabilities

I’m gathering that you don’t know what the word “ambidextrous” means. The prefix “ambi-“ means “both,” as in you can use both hands equally