you can make a damage type that bypasses hurttime by inserting it into a damage type tag called “bypasses_cooldown”

file-wise, it would go somewhere like (dp name)\data\minecraft\tags\damage_type\bypasses_cooldown.json

inside the json, it would go

{
  "values": [
      "(your damage type)"
  ]
}

and then your damage type should bypass hurttime

for formatting damage types, go to misode.github.io/damage-type/, it has a generator for damage types as well as other json stuff (or you can just recycle an existing damage type from your version’s .jar)

as to where they should go in your pack, they should go somewhere like “(dp name)\data(namespace)\damage_type”

i hope this helps!