Most of my playlists are actually by artist. Silly as it sounds I will put whole albums by the same artist in release order into new playlists by their name so I can just ask Siri to “play playlist <artist name>” and listen to the albums in order as I tend to listen to whole albums. The other playlists are like my year in review playlists that were automatically generated and some curated playlists like “weekly new music” and “top alternative” type stuff that I didn’t create but added and listen to often.
If I want a mix of stuff I like, I don’t turn to playlists anymore and instead I just ask Siri to “play some music” because the “just for you” radio is so good that I get tons of hits and top songs for my own taste as well as discover tons of new to me music that gets sprinkled in that the algorithm finds for me.
If the “play some music” stuff ends up not what I want to hear right then, I’ll just make the same request again or “play some different music” and it will switch to other music it knows I like. This is helpful when one request sends me down electronic path when I want more alt rock, etc.