There IS no magical answer. The game design philosophy indicates that.

Imperials have fragile ships, with high green dice, and low-middling firepower. But cheap. (As a general theme)

Rebels run tough ships, with low green dice, middling-high firepower, and are more expensive.

That was the concept for the entire "base standard" of the game before we got things like Decimators or Z-95s being added in, and is why Imp vs Imp and Reb vs Reb is never as interesting as when the factions play their enemy. A standard TIE averages zero hits when flown against itself. However when flown against an X-Wing then an average of 0.5-1 dmg goes through on each ship. This ensured that things actually died.

Now you're trying to play a TIE against a super TIE. When you average 0 dmg against a normal TIE, then of course you're going to have a bloody hard time hitting something with 1-2 extra green dice on top of it. There's no "tactic" you can use to invalidate probability and game design in this instance. If you do not have the tools to deal with a problem, you find a way to minimise the problem's effect. In this case, that means blocking it as much as you can without sacrificing your ability to take out the rest of the list, and then end the game (if a friendly match) or try to reach the end of the game having lost as few TIEs as possible (if at a tourney).

Can I weigh in on this?

Against one Phantom, you need to be prepared since turn 0. That means asteroid placement that is substantially different from the normal setup I've described. They have to be in the centre, but loose enough so you may pass in certain areas. The idea is not to block all the options of the opposing phantom, but some.

The other trick with the phantoms is it's a number's game. So firing with all your ships is perfect, barring bad luck. I actually think a range 3 engagement where you have everything pointing at the phantom is great. Your own phantom can't die during your first turn because you have evade (barring Direct Hits lol). So with this type of engagement you might take a shield or two. Next is a game where you either block decloaks or get range 1 shots on possible locations, forcing him to a worse position, preferably one where he can't fire effectively, while firing with your own phantom. This is why ACD is important on the Sigma, it gets you a degree of freedom necessary to threaten his own phantom. I actually ignore the escort.

The other point is that the Phantom has more options the closer it is to its target and conversely very few when it's far away. So on the initial engagement you should be able to get a distant shot with most of your ships, as I said.

It's a very difficult matchup, but I think it can be done. Echo + Whisper on the other hand is pretty much impossible. You're counting on your opponent making mistakes and you being in the position to capitalize on those. If memory serves me right I won once against that type of list with a sigma swarm, but if it was as I remember, positioning and pretty good dice were key. In the current meta you should be hoping somebody takes out the double Phantom list, because it's a terrible list against all the turrets we currently have.

I've defeated phantoms with Soontir Fel and Carnor Jax, but i've lost to the same phantoms with those guys. Will of the dice and risks usually.

green dice do fail but the TIE's firepower often isn't enough to seal the deal...