Is an encrypted backup necessary to upgrade iPhones?

I had always thought that I should encrypt a backup of my iPhone onto my Mac every once in awhile and especially before I upgraded iPhones. It took me hours to figure out how to find the iPhone on my Mac when I connected with USB. I have tried the encrypted backup and it just sits and never finishes. Running Big Sur 11.6.5 and iPhone iOS 14.8.1. Would prefer not to update Big Sur because I don't have any time for any other mishaps. Thanks for any advice