How to synthesize research articles?

Hi. It has been three weeks now that I’m still trying to write the literature review chapter of my thesis. My research is about the unfavourable impact that technology has on employees at the workplace. And for this, I obtained 61 research articles and papers from libraries and DOA which are really useful. So, the problem is that I reviewed all of them, finalized 20 research papers and prepared detailed notes. But I cannot synthesize the 20 sources which then are troubling me in writing LR. Are there some tools or any easy peasy way to get done with it?