For generating a cookie file, I suggest just using https://github.com/hrdl-github/cookies-txt
I should really write up a full Linux and windows setup guide and submit it.
Likewise, people who use bandcamp are likely to use GOG, which also has purchase archiving tools available on GitHub. I’ve used https://github.com/Kalanyr/gogrepoc for a long time, but there are actually multiple projects now.