There are two constants to look at here. Airflow and fuel. If your temp is not high enough, one or both of those constants is in short supply. Your air intake and exhaust numbers seem to be in line with a good setup. Can you post a photo of your charcoal basket? You might simply not have enough charcoal going to get the temp you need.
Kamado Joe Big Joe ° Kamado Joe Classic ° Old Country BBQ Pits Brazos Offset
UDS ° Traeger Lil' Texas Elite