Hello,
Sorry if I missed mails with this subject. Why do you want to install TDE on an old Debian ? (computer too old ?). Because with a SSD hard disk, Linux can work fine, even if the computer is old, not so slow, and Debian-Bookworm will accept the last TDE version.
Old cars are better than new ones, including mine, and also my old Dell computer too. Why to change them ! :-)