I have a 1/2 hp Superior sump pump I got via Amazon. Harbor Freight pumps will work too.
However, if you are draining a large volume it is likely better to rent a sub pump from Home Depot. If you time it right, you can pump out what you need within the minimum 4 hour window for the pump rental. Cost is typically about $50 and they should include the hoses. Do have where you are sending the water effluent to decided ahead of time. Each municipality has their own requirements.
The garden hose is convenient for most people but the flow suffers. I bough an adapter coupler for the hose outlet and connected mine to 1.5 inch sprinkler pipe that I had leftover from other projects. Even at 75 ft the flow was many times what the hose would have been.
if you have the 24 hours to spend, the small pump is fine if you modify the outlet. If you want/need it done in a few hours, the rental pump is the way to go.
And regardless of how much you are draining, it takes about as long as it would to fill that amount with a garden hose. If you were draining the whole pool, it would be days. But it brings up a good point about buying one anyway. You can modify it now for more output, but you’d always have the garden hose option if you ever needed to do a water exchange. It would pump through the hose about as quick as you could fill the other end with a garden hose.
Buying the pump now would come in handy one way or another down the road. Or you could buy one just to have and rent one for this bigger project.