Some kind of academic CRM where you can start a new 'project' with some keywords and it assembles highly cited works and the authors of the works.
From there you can recursively search through the bibliography of the seminal works and the works that cite the seminal work to build a research map.
When researching different fields you often end up finding a) who the top researchers are and then you want to go read all of their stuff. b) who is currently working on the thing in $current_year who you might want to contact and talk to.
for example, when it comes to internal combustion engine research, Heywood is the man: https://scholar.google.co.uk/scholar?hl=en&as_sdt=0%2C5&q=JB...
(most cutting edge research is locked away in the automotive company's sadly).
Or in computational fluid dynamics the 'entry point' to the field is basically JD Anderson.
In both cases you're like 6 degrees of separation away from the cutting edge in several micro topics of active research.
> synthesize them into a coherent mental model to inform your own research
For the mental model there's no real way around sitting and reading a bunch of papers, I basically taught myself how to read papers efficiently and then read papers every day (often dead ends which can be quickly discounted.)