XPS 15 7590, Using a Type-C charger

USB-C only guarantees 45w.

There is no 130W usb-c standard.  100W is max

USB Power Delivery (PD) specification

Source output power

+5 V +9 V +15 V +20 V

Unfortunately speedstep's information is once again a mixture of partially correct and completely incorrect.

USB-C all by itself doesn't "guarantee" any wattage level.  It is required by spec to provide at least the default 5V for backward compatibility with USB-A, and the standard minimum amperage level for a powered USB port that only supports USB 2.0 (which is all certain USB-C ports support) is only 500 mA -- so the minimum guaranteed wattage would only be 2.5W in that case.  I have no idea where speedstep came up with the 45W figure.  There are plenty of USB-C chargers that can provide more than 45W, but there are also plenty of chargers that can only provide less than that, such as 15-30W chargers.  And then there are chargers that have a USB-C port but don't support USB PD and therefore only support the standard USB power levels of 5V at 500-2100 mA, i.e. 2.5-12W, and possibly some proprietary standards like Quick Charge 2.0/3.0. Some early phones with USB-C ports used those standards for fast charging instead of USB PD, and therefore their chargers supported those standards but not USB PD.

It is true that 130W is outside of the official USB PD spec, which currently maxes out at 100W.  But it is also true that Dell did develop a proprietary standard on some of their docks, chargers, and systems to run 130W over USB-C  So even though there is no industry-wide standard for 130W, there is a vendor standard for Dell.  130W over USB-C has been available on the XPS 15 models since the 9550 that came out several years ago and on the WD15 and TB16 docks that also came out years ago, and that capability has since been implemented on newer XPS 15 models, newer docks, and the Dell 130W USB-C charger.  That charger was introduced with the XPS 15 9575 2-in-1, because it required 130W but Dell only gave it USB-C/TB3 ports rather than a barrel-style charging connector, which is why they developed the 130W USB-C charger in the first place.

It is also true that current Dell systems seem to limit themselves to 65W (not 45W) when charging over USB-C from non-Dell chargers, even if the charger can provide more and the system would benefit from more.  But since the question here is about using Dell's 130W USB-C charger with a recent Dell XPS 15 system, that wouldn't apply.

And although the USB PD spec supports all of the voltage levels that speedstep listed, USB PD chargers are not required to support providing all of those voltage levels.  The only mandatory level is 5V.  And in fact I've read elsewhere that the Dell 130W USB-C charger only supports 5V and 20V output, which creates some limitations.  If you have a device that only supports being charged via 9V and/or 15V, it won't charge from that Dell charger.  And if you have a device that can fast charge over 9V and/or 15V but will otherwise only charge at normal speeds via 5V, then that device would only charge at normal speeds from the Dell charger.  For example, recent iPhones support 18W USB PD charging.  Obviously 18W is well within what the Dell 130W USB-C charger can provide, but iPhones only support receiving 18W as 9V at 2A.  Since the Dell charger doesn't support 9V output, it wouldn't be able to provide 18W USB PD fast charging to iPhones.