when one wing is lower than the other, the lower wing produces more lift bcoz of higher AOA to the sideslip velocity of air.
I'm unable to understand how is that the AOA of the lower wing increases wrt relative wind coming from sidewards(lower wing)?
Without sideslip, the AOA may not increase, but the vertical component of lift will be greater on the low wing because it will present more area in the horizontal plane.
With sideslip, a swept wing will also present a longer effective wingspan to the airflow.