Amp hours and watt hours are related by voltage since 1W = 1v x 1A
Therefore since the portable battery pack is using lithium ion cells with a nominal voltage of 3.7v: 20,000mAh x 3.7v = 74,000mWh = 74Wh
That's actually more than I was expecting, I don't know why, I guess we all learn something new every day. It's also more than the framework battery, though I wouldn't expect it to be a straightforward 1 1/3 charge for the laptop since there will be inefficiencies in the system. I hope this helps!
No, that's CAS latency (CL) 46. I don't know if anybody has tested exactly how much performance difference that will make but it will be slightly worse