Tce-uninstall has simply been removed, it is not possible to properly support it without being integrated into base functions, which will not happen as that would be a performance penalty as well as hinder development.
Tcz-uninstall has been retired and archived (search forum for thread). I personally use it daily in extension testing and it is pretty safe with it's final changes made to it before it went on the shelf. It is available as a script but not part of the official repo nor is it supported. Still, removing the extension from the tce directory and rebooting is always the best way to uninstall.
For a PPI install, my advice would be to save the tce's it was made with, clear the tclocal file/directory, and reload the installation every so often to avoid system rot. That would be the way I would uninstall from a PPI, just clear it and reload it with the packages you want.
In other words, uninstalling on the live sysetm is not a TC concept. The supported method involves rebooting to a clean state.