VirtualBox: external remote via host IP to guest OS vs. udalenka on local IP of this guest OS from VPN?

Question

RDP

Someone who knows can enlighten how much responsiveness the described schemes differ (and at the same time comment on the connection scheme in terms of how what goes and where the lags come from)?
In general, such a topic. I "pumped" the system on socket 1155 in 2011 almost to the eyeballs (xeon-1230v2 + 32GB of RAM, 1290 zion is not enough =)). With this layout, you can keep at least one virtual machine with Windows in the background on a permanent basis.
And here's what we have:
- my computer host is behind the router, the router is registered in ddns to make life easier
- a VPN server is running on the router, I made the pool so that virtual clients are on the same subnet with real network clients
- VirtualBox is installed, in virtualbox rolled up for testing Windows 10 (network in bridge mode), configured remote access from the program with its own port
- in the guest Windows 10 also set up remote control
So. It turns out that there are two ways to steer a ten.
1) By remote VirtualBox'a directly on the external, that is , domain_name:port_virtualbox
2) By remote Windows 10 at the address of the local network, after connecting to the VPN server running on the router
I tried only 1 method with an external 100 Mbps and ping 2 -4 ms and over the local network, but without VPN (Something in the router does not respond to the server and I'm still sorting it out). Locally more responsive, of course. But how in terms of responsiveness will the connection in 2 ways with VPN show itself? And how does it differ from method 1 in terms of connection mechanics.
thanks in advance