I think at this point we can reasonably conclude:
- The PVE is working properly.
- PVE services are up and running, that includes SSH and PVE API/Web.
- The ARP and ICMP traffic appears to function on your network, however TCP traffic is being blocked by something.
Unless you made firewall modifications on PVE, the PVE does not block such traffic in basic installation.
The problem is in your network. Possibly network switch (did you try to reset/reboot it?), possibly custom windows firewall.
You will need to invest time into troubleshooting your network. I would retry the direct cable connection. Most modern NICs are auto-sensing and are able to work with standard cable when connecting direct. Its possible that one or both of your NICs are not capable of such detection. You can try a different cable, a different Workstation or make a cross-over cable. Also check the Auto-Duplex settings.
Another avenue for troubleshooting is tcpdump/wireshark. As you attempt your connections - run either one on each side, note which traffic passes through and which one doesn't.
good luck
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