The difference of PCIe passthrough vs GPU passthrough

It likely is not the Hypervisor that is locking up, but some kind of hardware (like the PCIe switch). You would have a hard time debugging this without any kind of PCIe debugging hardware and a whole bunch of PCIe-specific knowledge, so it probably is not worth pursuing. In general, PCI passthrough is not what you should use without a great deal of consideration.

If you need a wireless-connected interface on the virtual machine, consider using an external device (router/bridge) bridging the wireless network to a wired one and using a virtual interface from within your virtual machine connecting to this network. Another option would be using a USB-plugged interface together with a USB network redirector.

WHY are you trying to scp files this way, it's really not a particularly smart way of doing things, you know when you ssh/scp into the box you have to enable the 'remote support option' - well that's what it is, it's there for support - you can scp from it but it's a super-low priority thread and VMWare are looking to remove that interface entirely in future releases. Also if you're copying files directly there's no reason whatsoever to assume that they're in anything but a totally corrupt and non-quieced state.

If you're trying to just do VM backups there are lots of other methods out there, I don't use the free version but VMWare's VDR appliance works ok, there's other things like ghetto-VCB as well that use APIs that are designed to do this and won't limit you.

Basically use the tools that are there instead of trying to hack your own way around.