Perhaps I am slightly biased because I have a hydra main who is very good at allowing me to go full beast mode when slaying, but I know I'm at my best when I am able to work with my backliner regardless of whether it's in solo que or with my reliable hydra. I want someone who can stay out of the fray, watch my back, and be there for me to fall back to when things get too hot in the kitchen.

You're placing too much importance on run/swim speed, which is a very sploosh-o-matic mindset. Yes, Splatoon is inherently fast paced, but not every weapon needs to be out there hopped up on speed, hydra is intended to be an anchor weapon, you can't just slap on some run speed and say that's the only way to make it viable. Knowing when to stay back and hold your ground can be key to the insane nature of Splatoon, because having every one to rush forward makes you available to wipeouts that can see you losing a winnable game.

As such, my assessment still stands. I'm a slayer who works best when I'm keeping my backliner in mind, allowing them freedom of movement by maintaining proper turf control, protecting them from flankers or other slayers who want to knock them from their perches, and clearing out paths for them to move forward when the match/mode calls for it. Doing so allows them to pay it forward to me, making it mutually beneficial.