I agree. Maybe it's because they recently awaken that power and they can't use it for very long and probably aren't very skilled at it but I was still expecting more than that.
Hopefully the next time we see them use it in the future it will be more impressive.
We still have a bit more of wano left, so I'm willing to bet that this fight will focus on them mastering their awakenings, similar to how Luffy's fight with kaido focused on him mastering his haki.
Due to Kid's awakening, they can probably buy themselves some time to heal up. Yamato is there as well, which means they could probably hitch a ride and have big mom chase them up and down for some time until they're ready for a round 2.