And the low quality cheapo companies drastically overrate / embellishYes much like i over rated my panels to 3.5kva but my mppt will only convert 2.7kva.
Most of the high quality products really are only rating at 80% of true cell capacity - as cells will have some level of variance by batch etc…
I have a “1000wh” power station that has less real world runtime than my 537 wh big blue
The 1000wh also has Bluetooth or wifi so I’m sure that eats up extra battery and contributes