Where is Big Sur LaunchPad app?

Same place it has always been, in /Applications.

Hello LenInSebastopol,

Thanks for reaching out in Apple Support Communities. We understand that you need help finding the Launchpad. We're happy to help. In macOS Big Sur the Launchpad icon looks like a square with little squares inside with different colors. In the link below Launchpad is the icon next to Finder.

Check out the following support article:

macOS Big Sur

Cheers!

If you roll over the left-side Dock icons, does one display the name Launchpad?