The maximums are are GRBL settings, but it’s a little more complex than that, as acceleration and length of the rapid change how fast it will actually get (ie. if acceleration is low, but maximum is very high, you’ll never move far enough to actually get to that maximum). Set the acceleration too high on an axis and you’ll skip steps. Set the maximum speed too high, and you’ll skip steps. This needs to be carefully tuned to match the machine. The defaults you get when you set up your SO3 are good, safe numbers. You CAN go faster, but again, you need to know what you’re doing and work slowly.
You can set the rapid speed (G0) in fusion, and often in the sender (which can rewrite it in the gcode as it goes by). If you open your gcode file, you can usually see it set at the first G0xxxxx Fyyyyy. Depending on the post, it may be settable there…depends on the post, some set it multiple times.