Everyone gave good alternatives for where to buy music. As for the pipeline for getting them into your music server, I have Picard running in a container (a couple projects do this, search docker picard) and I have the settings all configured so that when I drop in files to my NAS (though samba or whatever), then I just double click the folder in Picard and hit save and it moves it into my music server’s directories, all properly and nicely tagged (I have the container volumes all set up properly as well)
You can look into beets or wrtag for more automation friendly tagging services.