@lebout2canap That's sad to hear.
I didn't try it yet, but https://flathub.org/en/apps/io.github.tobagin.scramble looks like a replacement, but it only supports images, not PDF, EPUB etc.
@lebout2canap There's now a fork of Metadata Cleaner on #Flathub: https://flathub.org/apps/io.gitlab.metadatacleaner.metadatacleaner