Other than installing various devices. I don't have room on my ship to install all those devices and be able to keep my defenses and attack power up at the same time.

you need to choose what build of ship you need for what you are currently doing.
imho scanners are useless for carting around all the time...only load up on scan if you are looking for new worlds.
cloak might protect you while you are offline but not as much as good attack/defence and stats(ie you are menacing or better)
so its buy and sell the ship parts until such time you have enough decks for what you need...might seem like a waste of money, but you cant buy a decent combat reputation any other way

Keep your cloak at maximum all the time. Protect you from hacking, and critical succes hack (the ennemy discover one of your planet).

Yes don't block it at all, but minimize the possiblity.