I have an EcoFlow River (first generation) that works great for this. It's a very manageable size - about 12 lbs - and has a capacity of 288 Wh, which is not big compared to the DJI models mentioned above, but it has worked great for me for...
I recently received my waiver for operations over people, which requires prop guards. DJI does not recommend using the plus battery with prop guards installed. Has anyone tried this combination?