Do not treat every multi-target attack as the same mechanic.
The C4 change limits the listed player offensive area skills to 20 PvE targets, without this limit for affected players in PvP or for monster and summon area skills. Polearm normal attacks have separate mastery and profession-dependent behavior; this does not establish a universal target count for every polearm user.
Polearm Mastery is a learned skill associated with polearm physical attack. A character equipping a spear does not thereby acquire every mastery level or specialist benefit. Check the skill levels available along that character’s own class path before copying another class’s farming setup. The weapon, its mastery and the attack skill each answer a different question.
Identify whether the planned damage comes from normal polearm swings, a player’s area skill or a servitor. Then inspect the corresponding skill’s target and range. A skill description stating increased P. Atk. with a polearm does not specify how many targets every swing can hit. Start with a manageable pull while checking your own learned abilities and available support.