Use the website
https://calibre-ebook.com/download_linux
This in a console always installs the current version on top of old.
sudo -v && wget -nv -O- https://download.calibre-ebook.com/linux-installer.sh | sudo sh /dev/stdin
Don't use Flatpak or any other distro version
Edit: I only use Flatpak or appimage if that is absolutely the only version. Mostly I use deb packages, except for programs where the deb doesn't exist or is too outdated or too updated or known to be "wrong".
Calibre, Viber, Brother drivers, Victron management, maybe Steam (I forget) all need website downloads.