What kind of tub spout connector is this?
I don’t know the brand but a plumber is not needed you could do it with a 45$ torch if you don’t have one.
I would pull the o ring and heat the end with a torch using players to hold the outer brass (yellow metal), make Sure to put some wet towels down as you slip the fitting off you don’t want the hot solder to damage the tub.  I like mapp Gas torches over propane they get hotter and make removal of sweated parts easier. Mapp has is the yellow bottle, my torch can use both types some built for propane can’t handle the higher heat of mapp gas. Then a new spigot for copper pipe could be installed.