Spent $400 on a cordless framing nailer that just can't keep up

I picked up a new cordless framing nailer about six months ago, thinking it would save me time on a big deck job. The battery life looked good on paper, but in real use, it starts to lag after about 50 nails. It just doesn't have the consistent power to sink a 3-inch nail into pressure-treated lumber every single time. I ended up having to swap back to my old pneumatic gun halfway through the first day, which killed my whole workflow. Now it's just taking up space in my truck. I should have just rented a good compressor for the week. Anyone have a cordless model they actually trust for full-day framing work?