I listen to NPR Up First podcast. The give you a nice overview in 10 minutes. https://www.npr.org/podcasts/510318/up-first

I worked for a very large insurance company until recently . IT is run like the Wild West. Contractors seem to do whatever they want.  after a merger several years ago, all the people who built the systems were driven out, leaving a bunch of low paid outsourced contractors to support everything. The entire IT infrastructure is a bad day from collapsing.