"I am totally new to anything engineering-related" so let's build a dangerous spinner with 2kg bar spinning at 2500-3000 rpm.

please just make a nice simple wedge bot. making a robot which can move well and make it through 3 mins of madness is an achievement in itself.

For drive just grab two cheap cordless drills and using the gearbox and motor. the drive for most FW. plenty of power and cheap.