I do not believe you can do a device passthrough in a proxmox container. Proxmox uses LXC containers which do not have the ability to pass a device through.
By default, USB will not passthrough to VMs in proxmox, you need to assign the USB device or port in your VM configuration in order for the VM to use it.
I recommend the following steps which I was able to do with Proxmox v7 and a Acurite 6037 console (Chaney instruments):
1. Create a VM in Proxmox. For my setup, I used ubuntu 20.04.03
2. I went on the shell of the proxmox host and ran lsusb. I looked for my weather station (eg Acurite) and recorded the usb address.
3. Started the VM and installed the O/S.
4. Stopped the VM and went under options and added new USB hardware. In Proxmox I selected the same weather station address and set it to passthrough.
5. started the VM and entered in the VM shell lsusb. I verified that my station was available.