Hand compactor vs. plate compactor
The metric I use is “Is anyone going to die, and will this last until I’m too old to care.”

A hand compactor is great for small areas, but to be honest, I’ve used neither up to 150 square feet / 12 square meters. Unless the slab is broken or unlevel, you have a great foundation and the slab will provided a good source of “levelness”.

The goal is to get the pavers level enough, with the sand underneath uniform enough, that any grade you’ve included for water management is maintained, and the pavers don’t wobble. That’s it — don’t overthink this.