The Amp ratings on both lead acid jumper packs, and Lithium jumper packs seem to have as much merit as lumen claims on chinese flashlights or the mAH claims of their used and rewrapped 18650 cells.
So much about whether the jumper pack can start the vehicle, depends on just how badly depleted the engine battery is. There are youtube videos showing these lithium jumper packls starting an engine with the regular battery unhooked.
The little 12AH AGM battery (UPG12120) in my long gone jumperpack had no issues jumping my 5.2 liter v8 engine, but back then I did not know how dead I had drawn the engine battery. They sell some of these smaller AGMS as "high rate" versions.
https://www.amazon.com/Cycle-Battery-Wheelchairs-Scooters-Mobility/dp/B06ZXTBSJR/ref=sr_1_2_a_it?ie=UTF8&qid=1515383812&sr=8-2&keywords=UB12120+agm+keykoI considered getting a lithium jumperpack a few years back. If I had one I would have only required it, to help others.
I've witnessed them work several times on cars which just had one click when the key was turned before applying the jumper, and with the jumper they cranked seemingly quickly.
Having them bake in the glove box in summer, or half frozen in the wastes of winter is another factor with Lithium.