ETS6 manages connections to the bus per project, with ETS5 this was a ETS-wide setting.
In the top right of your opened project there is a dropdown (showing “automatic” by default) which shows the way ETS will connect to the bus.
There are usually 2 ways to do so:
a) directly to the lan interface (ETS should list this with the found IP address of the KNX lan interface and the port 3671
b) by multicasting to the network via your local lan interface of the computer (which shows something like 184.108.40.206)
The second way is usually the easiest way to connect, but because of your vitualized windows machine the virtual network settings may interfere with that. Be sure to have the network of the virtualization to connect to your local lan network and not block multicast or broadcast.
I never used the BAOS 773 (which is an IP router, not just an IP interface) but it looks like an interesting device, offering access to all group addresses by web service. When using Home Assistant, ioBroker, gira Homeserver, … you won’t need that though.
And yes, welcome to the slow world of KNX ;)
Full application updates (or the first programming) may take a while, up to 90 seconds are not a rare thing. Later you can send updates to the devices which is faster. Firmwareupdates over the KNX bus can be even slower, for example my weather station takes 7 or 8 minutes for an update!