I had a cheap one of these some time ago and was initially quite impressed. I started my V8 soarer from dead, my V6 Sedona from dead and neighbors transit diesel all in one charge.
Used it a couple of times and then ot just stopped. It would charge completely but when used for anything other than a power bank it did nothing, so it went back still under warranty.
After some consideration I decided it was time for another one, but this time I wouldn't go cheap. Bit of research and some chat with some other people and I settled on this
https://www.halfords.com/motoring/battery-maintenance/jump-starters/gb70-2000a-noco-jump-starter-721906.html
But when I bought it last month it was £170, quite a bit more than my last one but I have to say a whole different class.
Gave it it's first charge which tool some time via USB and then off to the soarer.
The soarer hadn't been started for about 4 months and was completely dead..... Hooked it up and first go, straight into life
https://youtube.com/shorts/n8NeBLsvH08
So it passed..... But what about as a power bank?
So off to the house boat and a sunken boat (long story) and after 2 hours of continuous running a pump and the boat was empty and the porta power? Only one light had dropped, so plenty of juice left
All in all am very impressed with ot so far. I have emailed the manufacturer in America and they said to deplete it completely at times and recharge to full, so I will use it some more and do as they say.