If you are having issues with League of Legends crashing within ggLeap, here are a few things to evaluate.
Check if all graphics drivers are up to date.
Check if Windows is fully up to date.
Turn off all overlays such as GeForce experience (Riot article on disabling overlays)
In Windows, you can search for "MSConfig", go to the "Services" tab, check "Hide All Microsoft Services", click "Disable All", click "Ok", then restart. Doing this will allow you to see successively if there is a specific service causing issues.
If you continue to have issues, please start a conversation with our web admin support.