Swap usage always maxed out

I'm running a proxmox server in a production environment, and I always see that the swap space fills up after a few days from a reboot. The host has plenty of free memory and usually sits around 80% of 768GB in use, but the swap is at 100% 8GB/8GB. I'm not noticing any performance issues, but is it constantly writing to disk?

Should I be concerned?
I'm on 8.3.3

Thanks