It is relatively easy (currently) to take a playlist and back it up as a plain text file.
CTRL+A, CTRL+C from web or desktop puts a newline separated plain text list of songs on your clipboard.
Main risk is that the list is in the format of "https[:]//open[.]spotify[.]com/track/[song-id]", so Spotify may break the lookup of these IDs in the future.
> so Spotify may break the lookup of these IDs in the future.
Luckily, Spotify seems pretty good at backwards compatibility. `spotify:user:$username` still seems to work in the search-bar, must have worked for almost 20 years now, and given that artists themselves use those track URIs and IDs, I'm sure Spotify will be even more careful with those than search query syntax.
From the title I was expecting something like "how I archived my Spotify memories in a plain text file".