I’ve never used Proxmox, so I can’t say. But TLP is a utility that starts at boot. I’ve used it with virtualbox running, so if Proxmox runs atop a host operating system, I don’t imagine that it would interfere with TLP.

As an additional note, I usually set the min/max thresholds at 40/80, so the battery will charge any time it’s plugged in and below 40% and stops charging when it reaches 80%.