Well, there are tactics. For example, the Hive can send these celestial warriors into a permanent knockout with a high spell power. Despite their powerful ice magic. But at the same time, it might not work. Previously, they could be one-shot with cavalry... unfortunately, it was too simple a strategy, so I disabled it. By the way, the last wave has regular angels. You can throw them against the celestial ones.
I've long since gotten used to the suffering on my maps. If anything, there are always easier difficulties. You could call hardcore a kind of trademark of my work, but... in my opinion, there are plenty of maps on the forum that are more difficult.