Hello, as it currently stands the 1HP mutator is poorly implemented.
The idea is everyone is one shot by anything, which is fine. However, players are still able to recover health and armour via pickups.
This creates a snowball effect, where players who get pickups, can farm 1HP players, while they require multiple hits. This creates a severe gameplay imbalance, as well as goes against the entire point of the mutator.
Suggestion is simple, disable the pickups/ability to recover health. It will make 1HP a lot better to play, and not ruin the point of the mode.