VGA comes from the days of “not plug-n-play”. Digital DVI (DVI-D) added a new wire known as the DDC wire, which allows query of a monitor’s capabilities. VGA adapters essentially cut that wire (I know there are some which have a bit of a patch to add this, but it only works with monitors which have the digital DVI as well, and even then it might use an older protocol not supported). The Jetson GPU does not allow manual configuration and supports configuration only via the EDID protocol on that DDC wire, so basically you’ll have to stick with an adapter to digital DVI-D or HDMI. Sometimes people get lucky and a default display mode works, but otherwise you are out of luck.