I don't think if you can rank for any valuable keyword without authority and backlinks. The News sites are eating away keywords which have at least 2k-5k volume. Below that, there are many average authority domains competing to expand their traffic. Even if an authority site mentions easy kws in their article, then Google will prefer that over your new site having an entire article dedicated to it. So, in the strict sense, an extremely easy keyword is the one no one is competing for. If you want to make money, you need to target valuable keywords with a little competition.
As far as keyword research is concerned, they rank sites based on several metrics. For example, Moz shows difficulty based on the authority sites ranking on first page, Ahrefs based on several factors like authority, kw in title & URL, no of results etc. I manually check difficulty based on whether the sites in SERPs are struggling to rank or getting ranked by chance. If a web page ranks only because there are not many alternatives, then I'll consider it as easy kw.
Google is obsessed with authority. If you could create a page on Unicef about keyword research and write only a couple of lines, it'll rank better than many sites with informative content. Bing on the other hand prioritizes exact match phrases. So, if you have an exact match domain for search query, it'll be easy to rank on Bing without much backlinks. If you don't have authority & backlinks, it'll be extremely difficult to even show up in Google search results.