So I originally tried this with the supplied Shargeek cable and a 100W Anker cable, using the same 100W port like you did.

I also purchased a pack of no name, random, 90 angle cables that are 1ft…and they worked perfectly. I’m getting a sustained ~40w of charging while on and off now. Link for the curious.

USB C to USB C Cable 100W 1ft 3… https://www.amazon.com/dp/B0B5QJTT8M?ref=ppx_pop_mob_ap_share

I don’t know what’s different about this stubby cable…but at least I don’t have to return this powerbank now. My only guess is that maybe the Shargeek and Anker cable I used doesn’t support the PD standard that the SD uses?

I sent you a PM. Gonna do my best to help you get it back.