I have a 50 amp, 220V outlet in my garage for a future stick welder. Four prong outlet, red, black, white, and ground.

Can I make a pigtail and box with two 110V outlets and feed it from this outlet. Don't need 50A. I wasn't smart enough to spec. 20A 110V outlets in the garage, they all seem to be 15A. My wirefeed welder wants 20A.

Could I get 50A at 110V to feed a friends RV if they came by to stay for a while. I think that would depend on the size of the neutral conductor in the cable, right. Would it handle the 50A return circuit?

Don't need to do both at once either.

Thanks for any advice/information.