[ghaff]

I'm not sure how you solve discoverability other than personal recommendation from someone with similar interests. As noted, there are a ton of podcasts out there and many won't overlap with your interests, others are largely or wholly inactive, others are poorly produced, etc. The fix, such as it is, is probably to have a podcast reviewer who isn't in it for payola, who overlaps with your interests and sensibilities who makes recommendations on a blog.