I’ve got a rather bent disc rotor which is causing my brakes to not work but to rub loads, is there any way to bend it back so that it works fine or am I better off getting a new one?

just bend it back by hand, spin wheel, adjust until happy

Or use an adjustable spanned for better grip and leverage but same agin do it while it’s on the bike and rotate after each little push/pull until it’s straight.