Diskaroo does one job: it shows where your disk space went, finds exact duplicate copies, and clears what you choose, on your Mac and on Windows and Linux computers too. It's free: sign in with a free Bravely Account, map your first folder, then claim Diskaroo Pro in the app, free, for life. CleanMyMac does a different job, whole-Mac maintenance, and it's built for that. If what you used most was its Space Lens, Diskaroo gives you that picture as a treemap or a sunburst, with no subscription, on every Mac, PC and Linux machine you sign in on.
Can Diskaroo replace CleanMyMac? For seeing and clearing disk space, yes, and it's free.