The only thing I hate more than Cactuars are Tonberries, and in Final Fantasy 7 Rebirth they have their own version of this menace, which you must steal and defeat in order to complete Johnny's quest. As a very safe player, here's how to do all of this without getting too close to the literal knife.
How to Get the Tonberry King Pristine Crown in FF7 Rebirth
To make this fight safe, make sure to always attack the Tonberry from a distance. By keeping the fight away from the stab point, you will also avoid any dangerous instant-kill attacks. My recommended group for this is Cloud, Yuffie (with a Steal Materia), and Aerith/Barret/Cait Sith.
If you haven't spammed the move yet, Cloud has a long range basic attack that I really like. To activate it, dodge with Circle and then immediately press Square. It should unleash an air slice that can hit the Tonberries from a distance.
If Cloud has Enemy Skill equipped, use Sonic Boom to further boost its ATK stat. It's also a long-range attack!