I have a turntable, so going to my local record shops is a fun way to discover new music. It happens that one of the shops is highly curated and has a selection that I really enjoy. Buying physical media is my favorite method of discovery because it requires a commitment to the spirit of discovery and learning about new things. Even though my wife doesn't really share my taste in music, she's a really good shopping partner and always finds me something great that I've overlooked.
Heck, sometimes I buy music based on the album art. I've discovered some great stuff that way... Of course, I've discovered some absolute trash, too.
I'll also look at the "Similar Artists" section on Apple Music and have had some decent success with that. I found that the similar feature on Spotify did not ever meet my standards, though.
If there's an artist I like, sometimes I'll look at AllMusic to see what else they've done. Sometimes a member of a band does solo stuff or was also a member of another band, then I can go from there. AllMusic also has lots of other features, like "Related Artists," "styles," and "moods" to help find similar music.
I enjoy reading the reviews on AllMusic, but I don't generally agree with them. A lot of times I like the stuff that they give a pretty poor review to, and dislike the stuff that they enjoy.
If a TV show or movie has a decent soundtrack, I'll look it up on Apple Music and have discovered several artists that way.
I used to work at a bookstore and we got both "Uncut" and "Mojo" magazines, both of which come with a sampler CD. Sometimes I'd strike gold, sometimes I'd strike out. I don't know if either of those magazines still exists or if they still include CDs.
Least frequently now, I'll learn about new stuff from friends. This was the best when I was in my teens and twenties and friends were plentiful and, by some miracle, most of them had similar tastes to my own.