First, Ink Resist Up, no doubt about it, I tend to run it exclusively nowadays over stealth jump, because it's just so much easier to move around, and I really notice when I'm not using it, like escaping, I get jammed on the smallest patch of ink and get caught And killed. It's so freeing to just be able to swim around and not worry about the smallest patch of ink, also strafe similarly, making firefights much easier too.
Second, I think I'm one of the only people that likes ink saver sub, it's one of my favourite abilities, particularly with burst bombs and Splat bombs as I often find myself running out of ink, but only upon using my sub. I'm always careful with my ink on my main weapon, but it's my sub weapon ink during a firefight that causes me to run out, particularly with burst bomb weapons, so I tend to run some ink saver sub in most builds to make sure I don't end up stranded with no ink.
Third, I'd probably put Bomb Range up, on suction bombs it's excellent, especially on camp trigger fish, you can throw over the wall where the chargers usually hang out on top of from the other side, with just one main, so there's a lot of opportunities. I tend to run it with Splat bombs, suction bombs and probably disrupters the most.
Fourth, Special Charge up. I rarely go all in on abilities, but I like going all in on special charge mains and subs, with special duration and special saver mixed in there on specials like bubbler on Kraken, particularly on weapons that get them often. I'm still not great at using either as I either do it too soon or too late, but Special charge up is really helpful in playing around your special.
Fifth, Swim Speed up. For a while, I tended to disregard run speed up, because I always hold the squid trigger, and so I'm only on my feet when I'm shooting, now I tend to use it more on faster strafing weapons, but the one I've stuck by the most is swim speed up, allows you to get to the Action faster, and move out of people's reach quicker, also hunt them down quicker. I'm someone who likes to shoot, duck in ink and find another vantage point before finishing them off, and swim speed up helps that massively. It's also one f the most satisfying to get three subs of, with that distinctive pink squid being repeated. Damage up is another that's really satisfying to get three of that fist icon subs. Speaking of which, if we were doing 6, damage up would be my sixth.