You could use M-x find-name-dired to list the files matching a pattern in the directory and subdirectories in a Dired buffer. See: https://www.gnu.org/software/emacs/manual/html_node/emacs/Dired-and-Find.html

The manual also says that you could use the recursive flag for ls, but I’ve never tried it. See: https://www.gnu.org/software/emacs/manual/html_node/emacs/Subdirectories-in-Dired.html