LXCs VS Docker/Portainer

Been using tteck 🙏scripts creating lxcs to run services and seems like a breeze. Just recently deployed Docker/Portainer in a VM. Is it a good practice to create another Docker/Portainer instance to further segregate your services OR let say you have another instance for testing?

And what's preferable setup?

I've also checked k8s and as per most of the ones I read, if you are single and no kids, it's good to learn. So I'm definitely gonna pass on this 😅