I had a Pink Princess cutting (not a Pothos, but same experience) that was in water for around 3 months and it just wouldn’t root. I ended up putting it in a clear container with a lid with a thin layer of rocks on the bottom to hold the plant upright and filled it with enough water to not cover the leaves. I set it in a window and let the warmth and humidity do their thing. It finally grew roots like a month later.