This paired with a filter seems like it would do the job, and based on the enclosure you might be able to have a smaller footprint. No CFM data though.
I think box fans are used because that's what people already have around. When wildfires rendered our air here in the PNW unbreathable last September a lot of folks were scrambling for something that would work quickly. Waiting around for an SUV cabin fan to arrive and then trying to figure out an enclosure made that a non-starter.
They should, and probably stay closer to the rated cfm with a filter there. However now you need a 12 volt power supply instead of plugging into a normal outlet. Plus you need to design a housing for it.
Neither of these are hard problems for DIY, but they are not nearly as easy or quick as a cheap fan and some tape.
This paired with a filter seems like it would do the job, and based on the enclosure you might be able to have a smaller footprint. No CFM data though.