Risking sounding like a broken record, I always suggest Tiny/Mini/Micro 1L form factor office PCs. Lenovo, Dell, and HP all create ultra small office PCs that make great low power servers. A Pi will use 5-9w at idle, while these PCs will use 11-13w idle. They also use more standard components such as NVME drives, 2.5" drives, and replaceable RAM. Easy to find under $100 USD used, I’m sure you can find them under 100 euro.
Downloading music from YouTube will get you MP3s, but they will have gone through the YT compression algorithms.
Use Deemix instead. Downloads MP3s straight from the Deezer servers with all metadata and album art.