Does the air handler's location matter with DSS?

We've owned many houses in our 40 years together and this is the first one with DSS and also the first to have the air handler in the garage attic instead of inside the house . We bought this house in 2017 and there was no smell but ever since replacing our split HVAC system in 2019 we've had the smell. Could the lack of temp and humidity control be a contributing factor with DSS? Would it be worth the expense to move our handler into the house? I wonder if this is just the perfect storm of lesser quality aluminum and bad air handler placement. What do you think? Thanks!

source https://hvac-talk.com/vbb/showthread.php?2226605-Does-the-air-handler-s-location-matter-with-DSS&goto=newpost