The charge mechanic is very clunky, partly due to how slow it is and also due to losing your entire charge if you get hit, or if you only let out a tiny burst and stop early. The left click burst is also entirely useless
There are other weapons for Ironbreaker and Sienna that are stronger and require much less micromanagement and the tiny moments of fun that can be had with the flamethrower weapons is not worth the effort in getting them into that situation.
Having a charge/pressure meter that’s separate to overcharge, increased by holding right click or what have you, and decreased as you fire, would be one solution that comes to mind.