It's worked for me previously, Or so I thought.
In the proxmox NIC config for the CHR guest, you set multiqueue to the number of cores.. IE, 8 if the guest has 8 cores.
Once that's done (and rebooted). You go to system>resources>irq (In the CHR guest), and you can see multiple queues per interface. You can then specify cores to assign queues to as well.
This helped me overcome high interrupt load on core 0 of the host due to interface interrupts. However, It was ultimately more helpful to just PCI passthrough the interfaces.