I've bought my second-hand 5.5.2 Wii U in 2019. After following some tutorials back then it looks like this:
Wii U (hacked using Haxchi on a bought game, no cold boot):
- Main menu
--- Haxchi
--- Homebrew Launcher (Loadiine GX2 launchers, Retroarch, WUP Installer GX2)
--- Retroarch
--- WUP...