Weapons: Personally, I find more "Oomph" comes out of all cannon builds. If you want hull damaging weapons though, I suggest getting the KCB and sticking that in the aft weapon slot. Run four weapons in front.
Deflector: Fine for now, work towards a set.
Engines: Jem'Hadar are good for now, again work towards a set.
Shields: Use the Breen shields until you can acquire a better shield, such as a MACO or Reman shields, for capacity.
Eng consoles: Use at maximum, two Neutroniums. Fill the other Eng slot with either an RCS thruster or an SIF Generator console.
Sci consoles: Replace the Biofunction Monitor with an Emitter Array, preferable from Fleet Embassy stores.
Tac consoles: Use [Console - Tactical - Polaron Phase Modulator Mk XI] x4 instead, for starters, until you can upgrade to blue XIs.
- Single Neutronium and single monotonium engineering console required. The borg torps are what usually smash your hull and you should be running a high kinetic resist to survive them. These are not optional if you like to live.
- Highest Mk Shield with [Pla] mod on it of the variety you prefer. They are cheap on exchange just try to get a purple MK 12 if you can. Set ones other than maco are not great, fleet are good.
- Shield Distro Doffs are still amazing.
- Leadership Boffs are amazing.
- Borg Engine + Deflector are amazing even at Mk 10.
- Weapon power high enough to hit 125 cap, rest into shields. Your base shield power should be 55-60 before skill/gear is added in.
- Emergency Power to Shields 1. Use it, love it.
- Hazard Emitters II. As above.
- Tactical Team 1. As above.
- Distrubte Shields binded to your keyboard for mashing between tactical teams.
- Use yo yo maneuver to keep guns on target and some defense score, never be still. If you get tractor-ed and don't have a polarize hull or attack pattern alpha use evasive maneuvers it helps keep defense positive!
- Brace for impact will let you survive heavy torpedo fire. Also full shield heal with doffs. Learn to time it.
- Don't be afraid to disengage for a moment or two.
I tank tac cubes in escorts, the above is why I get away with it.
If it's just that, your gear setup, while there is still room for improvement (e.g. trade prefire chamber for a quantum or another polaron boost, remove biofunction monitor for anything else etc...) should be able to hold up just fine in ESTFs when using the Borg shields (Plasma resist).
Could you post your active Doff and Bridge officer setup? Having the right Boff skills and saving them for the right time, probably has more impact on your survival and your performance than your gear does. Good active space doffs also make a big difference. Especially good Shield Distribution and TacTeam-Conn officers can make your ship much more survivable.