I suggest to make "DEL" (or ESC) available for control setting

I tried to set DEL as an attack button for 2p but it wasn't working (because it was for un-assigning the controls setting)

I think one has to consider that many users who play 2p in a single keyboard use DEL a lot to make more space in keyboard to play for two players.

Is it possible to change DEL in controls setting (which unassign the setting) and ESC to other buttons like F1 or F2 that no one might use as a controls setting?

You're in the wrong section, friend.