What's the best way to ground a Jackery Explorer 2000 Pro power bank ?

[UKMeterman]

Earthing will make little to no difference. The 6m lead is acting as an antenna. Try this in a suitable box with the filter close to the power source. FN2020-16-06 | Schaffner, FN2020 16A 250 V ac/dc 400Hz, Chassis Mount EMI Filter, Fast-On, Single Phase | RS - https://uk.rs-online.com/web/p/power-line-filters/2192864?gb=s

 

[Avo Mk8]

Snap!

 

[UKMeterman]

Or even better try FN2070-16-07 | Schaffner, FN2070 16A 250 V ac/dc 400Hz, Chassis Mount EMI Filter, Wire Lead, Single Phase | RS - https://uk.rs-online.com/web/p/power-line-filters/7761156?gb=s