Hey, I have to chime in here.
The unit you're looking at has a bunch of negative reviews on Amazon:
https://www.amazon.com/9800mAh-Rechargeable-Protable-Lithium-DC1298A/dp/B074SJHH1XAnd, based on the unit's weight and reviews, it's possible that the 9800 mAh is based on the 3.7 volt cells, not the full 12 volts. So you may be getting 9.8X3.7=36 WH (or 3000 mAh at 12 volts)
That's not out of line for $25, but this looks like a bare-bones battery pack, with a shrink-wrap cover.
Myself and several of the TS members have been using the TalentCell lithium battery with good success, and I'd recommend it.
https://www.amazon.com/TalentCell-Rechargeable-11000mAh-14500mAh-26400mAh/dp/B01337QXMAI've run my UA5 with the TalentCell 9 volt output, and simultaneously run my Tascam DR680 with the 12 volt output, without issues.
You can opt for the 100 WH TalentCell model ($50) and fly with it as a carry-on without a hassle, or get a little extra power with the 132 WH unit ($65) and have to notify the airlines when you carry it on...
Hope this helps, and sorry if I muddied the waters!