Buy stock en masse with others and vote out the board and CEO…
That is how the other side has taken over corporate boards.
AT&T was having a lot of problems with the Communications Workers of America. At the time the CWA was either the largest or second largest union in America. The CWA decided a good strategy would be to have all of the union members vote their shares in order to get a CWA member on the board. They did an analysis and found out that if 100% of the members voted 100% of their shares it wouldn't even come close to having an impact on the election. The board controlled everything and nobody was going anywhere unless they rubberstamped it.