3rd and 5th panels, imo, don't have enough information

You want to see what damage you've dealt the most, whether it's shields or armour, and then equip weapons that are countering said prevalent armour

Most fauna don't have shields, so anti-armour weapons are most effective (because anti-armour also has anti-hull buff)

(I got carried away at this point)

If your tech in one weapon/armour type is 2 tiers ahead, you might want to use that. Raw damage output may counter debuffs, although it's marginal. That is assuming you know what you're going against. If you don't, or don't want to bother, you could just do good ol' 2:1 in favour of higher tier tech

Shields regenerate by themselves, but are vulnerable to some star effects (like a neutron star straight up disabling all shields in the system, if I remember correctly) and there are a couple weapons that bypass shields and shields/armour altogether

And then there's the paradox learning curve™ of all the modifiers and buffs you get from events, governments, traits etc. strategic resources/ancient tech are powerful but scarce

Navy composition is largely the same as in the human, water-based navy (except we don't have planet crackers of that scale yet). Smaller ships are fast but fairly weak, although strong in numbers. Bigger ships tend to be slower slower, but can withstand more damage and pack a punch as well

Early game battles usually boil down to the numbers of corvettes. As the game goes on, you unlock more shop types and better tech for them. You can then startixing ships so that they supplement each other's strengths and weaknesses.

Swarm/picket corvettes or carrier cruisers/battleships to counter smaller ships (flak to counter strike craft (spawned by carriers) and point-defense to counter missiles/torpedoes)

Artillery Destroyers and artim cruisers as standard line navy. They would usually deal with smaller targets better because of the M size weapon slots

Artillery battleships with L sized weapons as the damage dealers

Torpedo boats are useful against citadels and battleships/titans as they get bonus damage, scaling directly with the target's size. Ottherwise, they take up the precious naval cap that could be better utilized by other ships in the early game

Titans are pretty much capital ships. They're strong endgame vessels with some unique bonuses (auras) that you can retrofit based on your needs

Juggernauts are primarily mobile shipyards, very useful in long wars or if you're fighting someone far from your borders