According to this article in LA Times. Chargers rent is $1 annual to the company owned by Kroenke.
https://www.latimes.com/sports/story...0the%20stadium.
The only teams that own their stadiums and land are the Patriots, Panthers, Dolphins and Washington football team.
Even the Cowboys pay rent to City of Arlington. Only 2 million dollars a year but that is more than the Chargers pay, which is $1 a year.