Splined freewheels can be easily removed without the axle, so that should come off easily. When off, it will be easier to reinstall the axle.

As mentioned, a bench vise is easiest, turning the wheel counter-clockwise like a steering wheel.

If you don't have bench vise, a big adjustable wrench or pipe wrench will work. Brace the wheel up against the wall as you lean on the wrench.