You are absolutely right, keywords research, analysis and then taking the user intent out of them is one of the most important task related to SEO. There are various tools for this purpose but I still recommend to use manual method using google. Then I cross check with Ahrefs which is a very handy tool.
The next important task is key word grouping and use of the keywords in an article. There must be all the keywords in the article without stuffing. Yoast is another powerful tool that helps in this matter. But still I prefer to take the skill to next level where your brain guide you in a better manner and tools should be used only for a guide or support.
You can visit my webiste thepoolparadise.com to check and comment about my keyword research and article writing skills. I would love to take the constructive criticism for the improvement of my work.