Confusion about osmosis in Transpiration

Hi! I am studying transpiration at the moment for GCSE Biology and I’m a bit confused about it.
It says in my book that the water vapour evaporated from the mesophyll cells into the air space. Is this an example of osmosis since the water is moving across the cell membrane or is it only diffusion? Can osmosis apply to  water in a gaseous state and if so is the process enough to ‘drive’ the water from the cell and to make it change state. Or is it a gas in the mesophyll already? I would have assumed that there would have to be an external factor supplying the energy for the change of state before the water can diffuse. I don’t seem to be able to find any examples of osmosis from one state in a cell to another state outside a cell.
Also, it says that the transpiration stream ‘pulls’ water up the xylem due to the difference in water potentials. It was my understanding that the difference in water potential only ‘causes’ osmosis in the way that it provides uneven water concentration levels which eventually lead even out due to the net movement of water particles, so that overall it seems as if all the particles have travelled from one side to the other because they are somehow drawn to lower water potential but in fact it just appears that way because they have moved in every direction. Does that make sense? I understand Water potential to be a condition which allows for this effect to be apparent but It is not a force in itself. I think perhaps I am wrong though because I have heard that water molecules are ‘attracted’ to solute particles and thus slowed down when they are near them, but again I’m not sure if that is just a simplification made because that is what appears to be happening but is in fact powered by another process that is hidden!!
Sorry for such a long question, I tried to explain it as unambiguously as I could so it’s rather repetitive I’m afraid!
I would very much appreciate any help with my confusion. Thank you