Are you printing at that speed, or just travel moves? Either way, 750 mm/s is pretty high and I am not sure stock VORON is capable of those speeds, some modifications may be needed. Chances are your printer won't even reach that speed if you had not changed accelerations.
As for the print speed, you need to determine your hotend's max volumetric flow rate. This is how much plastic hotend can melt. If hotend cannot melt the plastic fast enough, you get underextrusion. That's usually done experimentally, some values for common hotends are published. Based on that, a bit of math is needed to calculate how fast you can print, as in, lay plastic down.
If you have Revo, with 0.4 mm nozzle, not high flow, E3D published their findings here
https://e3d-online.com/pages/revo-nozzle-maximum-flow-rates
From that, you can determine how fast you can print, find flow rate calculator, one is for example here
https://e3d-online.com/pages/revo-high-flow-volumetric-flow-rate-calculator
With common Revo 0.4 mm nozzle, you can usually print at around 180 mm/s. Increasing temperature or using high-flow nozzle can increase that.
To increase flow, you need hotend which can melt more plastic. That's why high-flow and ultra high-flow hotends exist. Then you need extruder capable of pushing that amount of plastic. Then you also need proper cooling to cool down melted plastic. Stealthburner can not keep up with cooling at such speeds you try. Your motion system needs to keep up with it too, and in order to make prints look at least usable, input shaper and pressure advance tuning is needed.
Printing 'fast' is not only about cranking up numbers. This is a rabbit hole to go down. If you have the time and money to upgrade printer to chase speeeeeeeeeed, you can find modifications, upgrades dedicated to this. Or just ... print. As fast as your printer allows, without producing ugly and weak parts.
