A drama series that follows three young aspiring fashion designers as the find themselves entangled in a power struggle against each other and the ruthless matriarch of the Australian fashion industry.

If this is a logline for a TV drama series best to structure the logline around the pilot episode and let the specifics of the situation that sets up the premise for season one form the logline.
Most TV producers want to hear a good idea that can set up story potential rather than the actual story of the episodes.

Must the story be about 3 designers, can it not be about 1?
What is the specific event that puts the MCs on a collision course with the industry matriarch?
What is the MCs goal?

Make the event that puts them in with the matriarch your inciting incident then give the main characters a description that would make it particularly difficult for them to achieve their goal.

Hope this helps.

Just one story comment. Aspiring people don't normally have enough power to take on an industry matriarch. You may handle this well in the story, but it jumped out at me in the logline. Entangled also tripped me up. You could drop it and it still works. Entangled is more for conspiracy or lies.

Power struggle also implies for control of something. Can you state what the struggle is over and therefore stating what is at stake and the goal.

Just needs a polish.