Ah yes, you’re looking at noise reducers.
AC Infinity Inline Duct Fan Silencer, 4” Noise Reduction Muffler Blower Silencer for Indoor Hydroponics Grow Tent Ventilation Systems https://www.amazon.com/dp/B0829GJ5Q7/ref=cm_sw_r_cp_api_fabc_.kjUFb0QK7C67
My filters are inside the tents.
Bought them.
AC Infinity Inline Duct Fan Silencer, 4” Noise Reduction Muffler Blower Silencer for Indoor Hydroponics Grow Tent Ventilation Systems https://www.amazon.com/dp/B0829GJ5Q7/ref=cm_sw_r_cp_api_i_AIImFbHC51M2J
yea, i know they are expensive, but it shows what is possible.
i understand you live in a small apartment but you could build your own fairly easily.
if you were to make a basic wooden enclosure with 2x4 and plywood, put some sound foam in the inside, a good quite fan (my recommendations are the following fan paired with the following silencer
https://www.amazon.com/gp/product/B0829GJ5Q7
https://www.amazon.com/gp/product/B06ZXWN3BG
just having the enclosure will massively reduce the nose.
you can really reduce the noise by using two layers of thin plywood separated by a 1 inch air gap.