a commonly agreed upon term

God, I wish. No, there’s like a dozen. Off the top of my head, I’ve heard

Survivorlike
Arena Survival
Bullet Survival
Reverse Bullet Hell
Bullet Heaven
Bullet Shooter
Survival Shooter
Autoshooter
Horde Shooter
Horders
Anti-tower defence

If any one of them gained prominance, we could have a steam tag, but nobody will agree, so here we are