realtime set macro button but not send setting.
That button, as you have shown there, would send the characters 0, x, 9, and 1, followed by an enter. Is that what you are intending to send? The macros are intended for standard GCode and other console commands, not special characters, and they do not work while a job is streaming because they could ruin the state of the sending job.
If what you’re trying to send is character 0x91, to increase the feed rate on a GRBL device, this is not going to work, and you’ll simply have to wait for that feature to be implemented correctly.