Isolation boundary between the application and the host kernel

Can we create an isolation boundary between the application and the host kernel?

(1) Is it possible with LXC/LXD Containers? How?
or
(2) if it is not necessary for LXC /LXD Containers? then why?

This question Inspired from google project :

Gvisor (https://github.com/google/gvisor)
weblink : Application Kernel for Containers https://gvisor.dev