I had a more aggressive filter but the first time I had an HVAC technician come look at my system he was adamant I use a lower rated filter. His point was the filter is just designed to keep debris from getting into the machinery itself not out of the air.

So I’ve got several HEPA filters running throughout my house instead. Not exactly as easy a solution as buying a higher rated MERV filter but certainly cheaper than a new HVAC system!