Welcome, toxonic. Congratulations on your first build being a success. So the experience you are having is very common. And by the looks of your excellent build, you haven’t done anything wrong. It’s possible for strong radio frequencies to invade audio circuits. That’s why we surround the circuit with the aluminum case that we are grounded to. That should take care of that sort of noise. Worse is the noise within our house or apartment wiring systems. Some of the noise comes from down the road and enters your house, and some comes from ourselves. Our refrigerators and washing machines, or even the neighbors, have motors which cause a fair amount of noise in the lines. Fluorescent and LED lighting causes noise in the lines and air. And then there are all the chargers and USB adapters, and yes, even the wall wart you are using to power up the pedal. My house is so bad that much of my gear is noisy even after passing through a power conditioner. Some of my small power supplies such as yours are unusable in certain spots and had to be weeded out. Bad luck for me here with a humming transformer on the other side of the driveway. But you may be able to try a different outlet with less noise. I would try a different power brick with more filtering too if you can. Cheers!