This is so unnecessary. Use the beauty and power of instantly and immediately putting a Debug.Log() statement into the very start of the coroutine, right at the top.
Do this always at the very first sign of trouble or question in your mind.
The instant you did this you would see “Oh man, this code is simply not getting run!”
And you could LASER-FOCUS 100% your efforts on studying what you expect to run it, eg., the call location, and isolate why it is not running.
You would look at literally NOTHING else but that issue until your resolve that one issue.
With that focus, you could also refer to any other successful coroutine anywhere else on the planet and go “Oh, I’m missing the StartCoroutine() wrapper!”