You are absolutely right. In my experience, being DQ'ed since August 2020 and waiting for an interview at the US consulate in Guatemala City we tried transferring our case to El Salvador around October 2021 as they had more interview slots and cases were moving faster there. Even though my wife has both Guatemalan and Salvadorean citizenship they shut us down pretty much immediately - to be fair she was not the main beneficiary so that might also be a factor.
As someone else already said in this thread, this case seems to be the exception, not the rule.