Dirty sock happens to all brands. The manufacturers still have
different opinions on what causes it. Most common on heat pumps in
high humidity aresa. Cleaning the indoor coil and keeping it wet fo at
least 10 minutes with disinfectant helps the most. Otherwise the
indoor coil (Evaporator coil) needs replaced with a heresite coated
coil. Trane now provedes a new coil 1 time for dirty sock, as does
American Standard as does Lennox as do some others.

Sorry to hear you had problems. My next system will have a variable
speed blower for sure!

Stretch