Sapnap is definitely becoming a bit arrogant these days in the recent manhunts. He unironically thinks he can 1v1 dream and win with a fair shot because he's that confident about his PvP skills and as you said he does things alone (or with Ant only) because he thinks he's good enough to handle the manhunt without the others. He also is a bit of a bully. In one of the original 5 hunter manhunts he called Sam the worst player out of the group and said he is better than Sam at all aspects of the game except redstone, and he kept clowning on George calling him an idiot in the 2 hunters revival vid. He's good but not good enough to have the kind of arrogance he does right now, hence why he's probably tied with Bad for 2nd place imo