Google has had the largest (or nearly so) lobbying spend for the past few cycles and in 2019 Facebook and Amazon are the top spending corporations. Spending a few million more than the defense contractors.

https://www.opensecrets.org/federal-lobbying/top-spenders

There is no database of PR spending, but it’s telling that a study conducted by Edelman, the worlds largest PR firm, found Tech to be the most trustworthy sector. A cynic might say they are pandering to an important client base.