Learned about this tool recently, for people who want (the now deprecated) Soundflower for Catalina. Installation was quite straightforward, testing it to see if it's a viable substitute to paid tools like the ones from Rogue Amoeba.

Fantastic. Tested and working for me, for all use cases. This is a free alternative to SoundSource by Rogue Amoeba. Good documentation too. Thanks Existential Audio!