To get KymographDirect working on Mac OS Big Sur, once you installed the LabVIEW runtime, type the following in a terminal:
defaults write com.company.KymographDirect2.9app NSGraphicsContextAllowOverRestore -bool YES
defaults write com.company.KymographDirect2.9app NSViewAllowsRootLayerBacking -bool NO
Then KymographDirect should run perfectly.