When you look at the graph of global warming it is dominated by cyclic changes like the solar sunspot cycle and the El Nino/La Nina cycles. They are much bigger than the trend caused by increasing CO2
If you pick a peak year as your starting point then you can make it appear to be cooling in the following few years. The same happened around 1945 and 1967. Each time the next peak was higher than the previous one because it is sat on top of the increasing trend. Over the 136 year record nine of the ten highest temperature years have all occurred since 2000. The missing one is 1998. I suggest you look at this NASA Site
and click where it says Global Temperature just below the graphic. I see no evidence of recent cooling.
Water vapour is indeed the biggest contributor to the overall greenhouse effect, which keeps the Earth perhaps 50 C higher than it would be in the absence of all greenhouse gasses. We are not discussing the overall effect but the change
since the start of the industrial revolution. You cannot explain that with water vapour. For example the amount of water vapour a cubic metre of air can hold depends on the air temperature. The higher the air temperature the higher the water vapour content. Thus water vapour is a major contributor to the overall greenhouse effect over the equator where the amount of water vapour is highest but has negligible effect over the poles because the air temperature is so low there is virtually no water vapour content. How then do you explain the fact that the temperature is increasing most rapidly over the poles compared to the rest of the planet? It can't be increases in water vapour.
In reality water vapour is an amplifying factor not a driver. As the air temperature rises due to increasing CO2
level it can hold more water vapour which raises the temperature even further.