I think it's great to have different suggestions of how to control or eliminate a fungus gnat infestation.
I just wanted to make the point that sometimes, the gnats start off as a symptom. For example, if you're watering your cuttings too much, one might get moldy and decay, inviting a stray fungus gnat to lay eggs there, which then leads to more gnats, etc. In this case, the fungus was the first organism to attack the plant, which opened up the floodgates for the fungus gnats. Then, once established, they will move on to healthy cuttings.
I mean, there is a reason they are called fungus gnats. I believe that is their preferred food.
So, if there if a fungus gnat problem, certainly try to eradicate them, but also consider whether there may also be some other problem, such as overwatering, or lack of ventilation. This might help success rates in the long term.
In my case, I think the problem got started from some potting soil I was using. So making sure you have clean potting soil, free of FGs, is certainly a good start.