I do not use playlists myself, but occasionally do use Classic fm radio, website and online play function is here,
I also get news from them, though being as they also play a lot of film score and some rousing things, I'm not sure you would call them relaxing .
Usually if I want something specifically relaxing myself I'll stick some Lorina Mckennit, some of Mike Oldfield's quieter stuff or something like Beahtoven's pastoral symphony, or a lot of things by Ludavico Ionaudi.
Generally though I will say I don't tend to use music as background, I mostly just do what I do anyway and if I want to listen to music I'll do that more actively. The only time I tend to deliberately stick on background music is when friends come over, and usually then it's something that we like and can comment on like a selection of good film score themes.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)