It is not a question of homebrew or CFW access on the console. The Wii U drive itself doesn't read standard DVDs.
Over the years overall drive security got better → no modchips anymore. In addition to that the interest in optical discs dropped next to zero. The perspectives for someone wanting physical backups aren't very good (while convenient USB loading is available on all Wii and Wii U). In the case of Wii games you might want to find an old, white RVL-001. The older, the better. Software and hardware modifications exist to read DVD-ROM, DVD-R and DVD+R (booktype set to DVD-ROM¹) on them. Note that "white RVL-001" is a necessary condition, but not sufficient for reading standard DVDs.
Even the last Wii drives didn't get modchips. There was some announcement for a "WiiKey U" but as far as I know it turned out to be vaporware and supposed to be an optical drive emulator. No idea if it would have been able to patch the drive for reading standard DVDs and BDs.
_________________________ ¹Some modchips get around the need for "bitsetting" DVD+R