Anker stuff is about double the price of what it was a few years back, at least partly due to the “just buy Anker” effect. There’s lots of stuff that’s better value for money, and a lot of the dodgier made-up mAh stuff isn’t common anymore.
If you’re buying a 20,000 mAh power bank some way to charge it quicker than overnight is desirable, which these days is USB C PD.