Timing out is unable to be fixed as it is often a connection situation, though it should only happen rarely.
If players die when being kicked from the server randomly then your server must have a settings, skript, or configuration that makes players die for some reason, this reason must be getting triggered by being disconnected. If you do not have any settings, skript, or configuration that is causing it, then the players must be in a position where they would die even without being disconnected... for example they might be in lava.