It doesn't look like you used the step-by-step I posted for creating a cc4c LXC in Proxmox:
BTW, it's no problem to pass an iGPU through to this LXC, but neither Chrome or Puppeteer really make use of it. It works when viewing something like Weatherscan, but I've never seen any other sign of hardware acceleration kicking-in.
If your Proxmox server has decent specs, and you follow the recommendations in the thread for vCPUs and memory, the LXC version of cc4c runs well without it.

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