And here's another vine about the same size but actually growing a new leave.

I'm no expert for sure, and some others will come along and give you good advice, but I find my pothos somewhat slow growing. I decided to give it more sun and moved it closer to the window. It definitely enjoys the increase in the sun because it has really perked up, but too early to tell if it will grow faster. Quite the opposite is my heart-leaf philadrondon, it grows new leaves/stems so quickly!