TNT rod by zduongz

1Repeat / unconditional / Always active

execute at @a[nbt={SelectedItem:{id:"minecraft:blaze_rod",Count:1b}}] run execute at @a[scores={playerHit=1..}] run execute at @e[nbt={HurtTime:10s}] run summon tnt

2 Chain / unconditional / Always active

/execute at @a[nbt={SelectedItem:{id:"minecraft:blaze_rod",Count:1b}}] run execute at @a[scores={playerHit=1..}] run execute at @e[nbt={HurtTime:10s}] run effect give @p minecraft:resistance 1 255

3 Chain/ unconditional / Always active

/scoreboard objectives add playerHit minecraft.custom:minecraft.damage_dealt

4 Chain/ unconditional / Always active

/scoreboard players reset @a[scores={playerHit=1..}] playerHit