ISSUE:
I noticed that the interaction entity does not fire damage events. This is half of what they're meant for. They do fire interaction events, but not damage events.

EXPECTED BEHAVIOUR:
I would expect that the interaction entity would fire the damage event. That is one of their main purposes. When checking their "attack" NBT value, it appears the attack is being registered to the entity.

Test Code:

@EventHandler
private void onHit(EntityDamageByEntityEvent event) {
    Entity damager = event.getDamager();
    if (damager instanceof Player player) {
        player.sendMessage("You damaged: " + event.getEntity().getType());
    }
}

@EventHandler
private void onTouch(PlayerInteractAtEntityEvent event) {
    Player player = event.getPlayer();
    player.sendMessage("You touched: " + event.getRightClicked().getType());
}

test jar included, how to test:

• plop jar in plugin folder and start your server
• spawn an interaction entity:

  /summon minecraft:interaction ~ ~ ~

• I recommend turning on hotboxes (F3+B) to see the entity
• right click on entity (you will see "You Touched: INTERACTION")
• left click on entity (you will see nothing)