Listening to various DJs has been my primary form of music discovery for the past 10 or more years. The diversity of and access to interesting DJ sets has literally never been better than now.

AM/FM radio is mostly irrelevant to this phenomenon, except as a precedent. Like you said, some small stations may be playing interesting stuff but the vast majority is over-commercialized, repetitive and/or boring. However, the internet has opened up tons of possibilities for DJs to curate and share music. Platforms include internet radio stations, Youtube channels, Twitch channels, and purpose-built sites like soundcloud and mixcloud. There used to also be a huge DJ blogging scene but that was mostly dismantled with DMCA takedowns in the 2010s(?).

For example, one of my favorite resources is NTS radio (https://nts.live/). They are a continuously streaming internet radio station that plays a wide variety of music. Every show they stream is archived for on-demand listening and organized by DJ name and genre tags. They also brilliantly address the demand for Spotify-style "background music" with their Infinite Mixtape feature, with music chosen by resident DJs.