Razor shows us how basic nen training can make you scary strong
People really do not give Razor credit for how strong he is in HxH. I think he single handedly shows us how important is raw Nen mastery and basic training are in the series
Razor was technically living in isolation for years in Greed Island. Did not have to fight many strong people. He did not have to fight for his life all the time or chase after enemies like the Phantom Troupe did.. When the Troupe met him for the first time they were careful and did not want to fight him even though they had more people.
People forget about the scene where Shizuku arm wrestled Gon for the ring in York New arc. When she lost and they went back the Troupe's hideout, I forgot which member said to her back then that if they really wanted something they would just take it by force. they had a mission to do on Greed Island and Razor was in the way of that, to me this means they did not want to fight him because they knew he was too strong. They understood that fighting him was not an idea.
Razor is strong because he is good at the basics of Nen and he practiced for years. He is an example of what happens when you master the basics for years non stop. Also the crazy part is his Nen ability is so basic and simple.
This idea also applies to adult Gon and to some extent to Netero (although he definetly had expericne coupled with it).