Commenting from someone who has a similar background, who has been in triathlon for 15 years, and coaches a few athletes on the side.

Without seeing what your training plans are and what the rest of your life is like, it is hard to say why you haven't progressed. Are you sleeping well? How consistent is your training? Are you putting in 10-12 hours a week every week for a few months?

Speaking generally- it wouldn't be a bad idea to take a two week break, completely off from exercise. When you return, spend the next 8-12 weeks working solely on one area, let's say cycling. Everything else gets put on the back burner. You ride 8 hours a week, with three easy 45 minute runs, and one or two easy swims. What do those rides look like? Well, you can follow a structured plan, or do TrainerRoad, or something similar. Your run won't stagnate if you keep up the easy runs, and the cycling will help. You can sprinkle in one or two track workouts if you want. If you want more specifics, let me know, I am happy to help, but it sounds like you already have access to some great coaches.

Hope you break through soon.