And that sprocket is going to be a sod to remove on a high flange Hub.................unless you have the tools
A freewheel remover is a great purchase, and they are very cheap.
First you will need to build the hub into a wheel though. Thankfully it's a high flange hub and you can get the spokes past the freewheel though.
Don't have to go nuts getting all the spokes tight though, a slack build will do to hold the hub still while you wind of the freewheel.
If you dont have a freewheel tool, and the freewheel is expendable, just crush it in a vice and turn the hub off it.
Still need to build up the wheel though!
The hubs are soft, so vicing the hub could squish it.