The standard Discord experience has you look for and join a "server", each of which is meant to feel like distinct island. This has every server duplicate the same set of boilerplate #general, #off-topic etc. channels, as if there are no others. As a result the vast majority of servers are fairly dead and barren, the userbase is spread too thin. Also because the UX makes switching between servers a fairly heavy context switch, so monitoring this deluge of channels is not fun and nobody can stay on top of all of their servers.
I once looked around for maker-y/electronics Discords, and joined probably 7-8, and they were all dead. ##electronics on Libera is highly active.