Lost music transferred to iTunes from CDs

I have lost all the music I have transferred from CD to iTunes over the last 10 years. I have always backed up all my music to iCloud. It seems that one day after an iOS update, every song was missing. What’s up with this Apple? Those songs were all purchased and legally downloaded. I’m very disappointed with Apple as it seems many users experienced the same issue. It took many hours/days to download to your platform and then you just delete anything g that wasn’t purchased directly from you?