I've been drawn to music since my early childhood and over the years bought a lot of music. I also read bits and pieces and later heard interview of the artist themselves. The Paul Stookey story I read in Guide Post. The Lynyrd Skynyrd story is pretty open and a lot written and filmed about them. Collins in his last years when confined to a wheelchair showed a lot of remorse. Hank Williams Sr I read about. Willie Nelson's Troublemaker album I bought on a whim in the ships store at sea. Best buy on a whim music wise I've had. The group Kansas the main writer and lead guitarist was Kery Livgren and has his own website both about music and ministry links. I read the lyrics also.
The song I find most depressing lyrics wise in Rock was "Imagine" not because of the music it was great. Lennon had lots of piano and writing talent. The Lyrics of that song though were an anthem for secular humanism and Communism. I could not stand the song once I read them. I hope he too in his final days came to Christ. We'll not know here on this earth.
As for Johnny Cash? Look up a movie called The Gospel Road. It is a video he and June did on the life of Christ. Cash battled addiction most of his life. One of his last pieces is "When the man comes around" a read of parts of the book of Revelation. He recorded it after June died best I remember.
Like I always said, "Ok, John, I imagined, and you know what, it sucks!"