Regarding point 1, USB-TMC is just as good as LXI, really. Completely industry standard, just like LXI or GPIB. LXI is great if you need it, but you probably don't if everything's on the same desk.

And there's even more instruments that just create a virtual COM port over USB and allow SCPI commands over that, and that's perfectly fine. You just have to configure it via something like [Keysight's Connection Expert program](https://www.keysight.com/us/en/lib/software-detail/computer-...) first.