Because this thread is two years old, could you please refine what you are having trouble with?
"Customize" page is completely empty"
Do any of the troubleshooting tips help you:
https://laytheme.com/troubleshooting.html#customizer-does-not-show-up
Some common debugging tests:
Wordpress, Lay Theme & Laytheme's Addons are all up to date ?
Any custom CSS or JS that may interfere is temporarily removed.
Talk soon & best wishes ✨ RichardAny third-party plugins are de-activated to see if this resolves the issue.