A key sequence is just one possible form of a command.
So you can just use the following form (if I understand your question right):
(global-set-key (kbd "C-t") (kbd "<backspace>"))
You can replace backspace with C-t by translating it in
(define-key input-decode-map (kbd "C-t") (kbd "<backspace>"))
(define-key input-decode-map (kbd "<backspace>") )
The second form replaces backspace with the ASCII bell character. The harmless
keyboard-quit command is bound to that character.
Note that there is already a duplicate of this question but the following statement in that question is wrong:
I also tried this:
(global-set-key (kbd "\C-d") (kbd "<DEL>"))
But it obviously turns every C-d key into , so keybindings such C-c C-d stop working, making this not a suitable solution either.
See also the corresponding comment of VanLaser:
You say "it obviously turns every C-d key into , so keybindings such as C-c C-d stop working" - are you sure about that? When you press C-c (or C-x, or C-h) another keymap becomes active, in which C-d should NOT be overwritten. As per this doc: https://gnu.org/software/emacs/manual/html_node/elisp/Prefix-Keys.html