For me music discovery is a solved problem. Here's the algorithm:
1) Imagine the timeline of musical history. If you don't have a clear idea of it, Wikipedia is a good place to start.
2) Pick any genre/period you don't know well. (For example, medieval music, or swing-era jazz.)
3) Look up the main figures of that genre/period. (For example, Guillaume de Machaut, or Duke Ellington.) Wikipedia is good for this too.
4) Listen to a sample of their most well known pieces. YouTube is good for this.
5) Repeat. Go down rabbit holes when you like.
No fancy tools needed, just your mind and the internet. This will give you interesting music for many years, and improve your musical taste a lot too.
Good advice.
However for some genres that approach won't work, since they are either too new, too niche, the genre-description says too little about the actual songs etc. If this is the case another tip is to go at it from the production/distribution/scene side. So you check music mixed by the same audio engineer, released on the same record label, made in the same city during the same time. This can get you surprisingly far.
There is no real shortcut to doing it yourself, part of appreciating that music is often also to understand the context within which it was made.
I agree this works really well and do it, this is essentially what I meant when i said 'clicking around music brainz and wikipedia.' That said I wouldn't be satisfied with this as the only way i could discover new music. There are so many dimensions that don't get codified in wikipedia or music brainz.