Thermite is considered less lethal than napalm and phosphorus. Its fairly direct too. It only lights up what it is dropped on. It can burn up cover and leave the troops under it fairly unharmed. Another example of Ukraine fighting with one hand tied behind their back, but still making due with what works.

On top of that, its super easy to make. Its just rust iron oxide and powdered aluminum. You can make it at home with a file and some old pipes.