Lot to go over here.
Because naut is a splatling, it really likes run speed. Run speed atacks better on splatlings than on other weapons (while charhing or firing, not normal running), and because they spend a lot of time charging up and shooting instead of swimming mid fight, run speed is what they rely on to be mobile in combat. Naut can swim in fights, so it doesnt rely on run speed as much as other splalings, bu it still really wants run speed up. Stacking swim speed is also really important bc of the charge old mechanic. The standard build for vanilla naut uses nearly a pure (19 ap) of run speed up and swim speed up each. So your hat is good but you probably want more.
The other 2 things id keep is the sub of special saver and a sub of qsj, each gets a lot of value from 1 sub, the second sub of qsj i would not say is worth it.
Splatlings in general like ink resistance, which is essentially run speed for enemy ink (and stacks great at 1 sub, 1 sub isused by basically every weapon) for naut, id make sure you have 2 subs, but not more.
Quick respawn is best for weapons that play really really aggressively and draw a lot of aggro, and dont have a lot of gear dependance. Naut is not one of those, so i would not use quick respawn.
Stealth jump is also something to consider, its a very good ability bc it lets you jump in much more often and closer to fights.
Id drop the special charge, splashdown good enough to invest that much in over more mobility and other things.
Sub saver is nice if youre gonna throw a lot of suction bombs, tho for naut it can be hard to find the time for that when you are charging, firing, or holding a charge so much.
Maybe you would like comeback, gives you a main of run speed, swim speed, ink recovery, ink saver main, ink saver sub, and special charge up for 20 seconds after respawn, its a good ability if you want to be aggressive.