Not sure this is what you meant, If not just reply with the skript you want but in more detail.
on chat:
set chat format to "&7[&e%{level.%player's uuid%}%&7] &7%player's prefix%%player%%player's suffix%&8: &7%message%"
on death:
add 1 to {xp.%attacker%}
on death:
if {xp.%attacker%} >= 5:
set {xp.%attacker%} to 0
add 1 to {level.%attacker%}
send "&a&lLEVEL UP!"
send "&7&oYou are now level %{level.%attacker%}%"
broadcast "&a%player% &7is now level &a%{level.%player%}%&a!"
command /level:
trigger:
send "&aYour level: &e%{level.%player%}%&e"
command /xp:
trigger:
send "&aYour level-up xp: &e{xp.%player%}&7/&e5"
@McHackLines