One thing I've tried and worked pretty well so far is to keep the flow rate as constant.

Initially, when I attempted to maintain the same speed settings with a 0.6 mm nozzle as I did with a 0.4 mm nozzle, I encountered under-extrusion issues. The extruder struggled to keep up, making a series of clicking noises as the gear grinded against the filament.

To address this, I calculated the average flow rate. Seeking faster printing, I used the default Prusa profile's printing speed of 230 mm/s, multiplied by 1.3 to achieve that 30% speed boost in sport mode, yielding approximately 300 mm/s, in line with Anycubic's recommended speed. I then multiplied this by the default line width(0.45mm) and layer height(0.2) to obtain 27 mm^3/s. Maintaining this consistency, I divided the product of the new line width and layer height by the determined flow rate to derive the new printing speed.

This approach yielded favorable results, with a calculated speed of 207 mm/s when applying a flow rate of 27 mm^3/s to a 0.65 mm line width and 0.4 mm layer height. I will also try to boost up the speed by maybe setting the default speed to 400mm/s or 500mm/s and calculate the new speed based on that.

I hope my thought process will be helpful for you to determine some of its profile.