I used Trelegy for 5 months, during which time I noticed a real improvement in my breathing. I walk a lot, and the uphill stretches were much easier. One downside was that I often wanted to clear my throat of mucus, and my voice was croaky. It was very difficult to clear my throat - a lot of huffing and coughing required for a tiny amount of mucus. Exhausting.
BUT - what made me quit using Trelegy and really scared me was the effect on my eyes. My vision became blurry, and I had a sense of my eyes being pressurised when I lay down in bed at night. The optometrist, worried, referred me to the eye infirmary, where further tests revealed high pressures, thin corneas, and early glaucoma. None of these were present previously.
My advice would be to leave this drug well alone. The risks (read the leaflet!) outweight the benefits.
It's your eyes for goodness sake! How on earth was this treatment ever approved for use?!