Use this block list you will have Spotify Free as Premium goodbye advertising
[spoiler] https://raw.githubusercontent.com/CHEF-KOCH/CKs-FilterList/master/Corporations/Spotify%20Ad-Free/CK's-Spotify-FilterList.txt
https://raw.githubusercontent.com/CHEF-KOCH/CKs-FilterList/master/HOSTS/CK's-Spotify-HOSTS-FilterList.txt[/spoiler]
Another option
Spotihosts
Scripts for add to your hosts-file the neccesary lines to block Spotify ads (web and desktop app).
The scripts must be opened ad admin/root to be able to edit hosts files (Windows and Linux)