i dont know what you know and dont know but at at a high-level. i needed sbanzbd to go through a vpn. so i installed sbanzbd on the same docker vm lxc as gluetun. if a different container needed access to gluetun i woild have to use its builtin proxy
Proxmox
Proxmox VE is a complete, open-source server management platform for enterprise virtualization. It tightly integrates the KVM hypervisor and Linux Containers (LXC), software-defined storage and networking functionality, on a single platform. With the integrated web-based user interface you can manage VMs and containers, high availability for clusters, or the integrated disaster recovery tools with ease.
It sounds like you do want to set the default route to the LXC’s address. Then set individual routes for the local LAN and cluster traffic. The routing table will prefer the more specific route (e.g., if you’re trying to get to 192.168.0.14, it will prefer the route you set for 192.168.0.0/24 instead of the default, which is equivalent to 0.0.0.0/0).
Don't
I don't see a usecase
Just because you don’t, doesn’t mean there isn’t one.