For 15 years now I use a compressor from an old water cooler that was scrapped out. It is quite and last forever, I have a gasoline fuel filter before the compressor to stop any solder etc. from the unit I change once in a while. It have been the best thing I have found. I also use a small cylinder for volume and a solenoid valve to go between the compressor and iron.
They are lots of them around and usually can be had free, or for low dollars.
Just a thought for you
Saw years ago when a shop used this system for 6 techs at a work bench.
It is very quite.