Sharing your current settings would help, like your speed, layer height, perimeter/wall count, infill percentage, supports, et cetera. How you're orienting the part on the build plate can also affect the print time and the amount of supports you use. Are you using a built in Cura profile for the Neptune 3 Plus?
However, 5 days isn't out of the ordinary. My Morrigan helmet is coming up on four days total on my Ender 3v3. I'm doing 5 walls, .016 layer height, 10% gyroid infill, organic supports, 150mm/s - 300mm/s. My Commando helmet took almost six days on my Kobra Max. It's not hard to imagine that if you attempted to print the entire helmet all at once that you'd see similarly long build times, even if your printer's capable of higher speeds.
