It scales based directly on your Team Power - in this case, the power of the defending team is less than half the Team Power value.
It’s also a team composed of heroes that are… less than optimal.
The problem is that if you don’t have a rounded roster, you’re heavily reliant on those top 5 being capable of completing most of the CW by themselves, because none of your other heroes will be up to the task. As can be seen in the video (y so long?! ), heroes that are 2+ years worth of ranks behind can’t do much.
The best way to carry weak heroes through CW is by just featuring a couple at a time helped along by your strong battlers, but you’ll still run into difficulty without a deeper roster - especially if those battler’s ranks don’t match up to their power values.
Invasion breakers scale based on your Team Level, but here too there’s no need to throw an entire team of collection heroes at them. When a new collection releases, I can often complete it that same week through breaker quests, even if all my collection heroes are purple and not even the right colour team. Just use your good battlers to carry a few at a time.