At a certain point, it isn’t room treatment, it is soundproofing.
I can measure the ambient noise in my room during the day and it is around 33 db, C weighted, on an uncalibrated SPL meter. (I have several and they are all within the same range). That’s quiet, but not dead quiet.
I can get there by inserting into the windows, sheets of melamine, sandwiched with mass loaded vinyl, which kills sound dead (like the roach killer). The extra few db of quiet might be important on a quiet record.
Measure your ambience noise when the system isn’t playing.
There are ways to quiet the room. But don’t think of it as "interior acoustics"- think of sound as the alien force trying to get into the room and block every point of entry with something that kills it. I’ve done it in several contexts- it is do-able- I have a compressor that powers my tonearm and it is in a silencer box that is lined with the stuff mentioned above. I did a walk in closet in NY with acoustic blankets and mass loaded vinyl against studs on top of dry wall, and plugged the pass through cable channels with Magic Eraser (melamine). I also sealed the door. You will hear any "leak-through."
Sounding proofing is entirely different than acoustic treatments. It’s not tuning, it is blocking and killing sound.
PS: the ’Hood chat board is a constant complaint against leaf blowers. It’s become political. Leaf blower wars.
PSS: the frig is different and has two aspects- the sound of the thing making ice and doing its thing- as they get older, they may get noisier- but it is mechanical, and the electrical jolt when the thing kicks on. Two different things, with two different solutions.