2 Pack 3.7 Volt Ni-MH Rechargeable Battery Button Top 9900 mAh High Capacity 3.7v NiMH Batteries for Flashlight Headlamp

I mean, they allow this: https://www.amazon.com/DQGG-Rechargeable-Capacity-Batteries-Flashlight/dp/B0GTTZNQ2Z - there's no way those are 10AH cells but that's what they're sold as. In any case, buy cheap, get cheap. The pack could have simply been poorly balanced, mismatched cells, or B grade cells - all things that can result in the pack showing far less power than expected assuming the ratings of the individual cells are correct to begin with.