What OP describes is a function of the utter failure of the "positioning" stat. It's meant to encourage small taskforces and limited engagements but it just isn't fit for purpose. It can't even be modded out; even mods that make positioning extremely impactful still reward "deathstacking". Just with fewer, more powerful ships.
Carrier overstacking works (kinda) but because it's only for the one ship type, it just makes carriers worse.
Really, navy needs 3 things
1) Positioning overhauled or replaced with some kind of combat width system similar to land combat, or carrier-style overstacking
2) Overall balancing (Air vs navy and the value of heavy ships being prime targets)
3) A UI rework so it's not infuriating for new players to use!
It would also be nice if Strike Force ships would automatically intercept naval invasions, rather than sitting there uselessly because the enemy got naval supremacy for 2 minutes and you haven't had time to set them to convoy raid; that would actually make navy more relevant to the overall game. And where is the ability to blockade ports!
Rn the way the underlying systems work is somewhat simplistic and results in this weird universe where Japanese kantai kessen doctrine is 100% correct bc against a competent opponent you will have one massive battle that irrevocably destroys the loser's fleet and grants the victor complete naval dominance in most cases. I wish they limited battles so you couldn't have these ridiculous clashes with 400+ ships engaging simultaneously and to encourage more in terms of stationing fleets in many places simultaneously like real navies did
Nail on the head!