>>111
I solved this issue as well now, the user simply needs to set vertico-resize to configure resizing.
(defun vertico--advice (orig &rest args)
"Advice for ORIG completion function, receiving ARGS."
(minibuffer-with-setup-hook
#'(lambda () (vertico--setup (nth 3 args)))
;; XXX When using automatic minibuffer resizing in a graphical
;; session with truncate-lines enabled there are often bugs which
;; cause the buffer to be resized to a single line bug#46718.
;; However in non-graphical sessions disabling automatic
;; minibuffer resizing can have the same effect. Further, it is
;; insufficient to `setq-local' resize-mini-windows in
;; `vertico--setup' on GNU Emacs 24.5.1 for unknown reasons.
(let ((resize-mini-windows (unless (display-graphical-p) 'grow-only)))
(apply orig args))))