I finally got uBlock Origin on my Firefox browser the other day, and one of the greatest things it's offered me is an ad-free listening experience on Spotify.
I use the web-based version of Spotify when on PC just for convenience, but it also means that web-based adblockers work a treat! I'll hopefully never have to deal with adverts interrupting me every other song.

I don't feel particularly bad about getting what is akin to a premium experience for free; Spotify can go suck a dick for all I care. Their business practices are absolute shit, but I haven't found a single other alternative that I actually like.
I might have a look for something new, but for the time being I'm going to continue with this setup.