We know that a wounded animal is a very dangerous one. If the Anunnaki decided to invade Earth, how would they arrive? Stargates? Spaceships? Both?

They are already here. The ships are already here, and many have been made courtesy of the United States government, and the troops are here courtesy of the Mercenary Army Program recruiting humans and subjugating them through mind control, in addition to the replication of humans to create a robot warrior instrument as a weapon. There is more than enough firepower already present on the planet to do the job. What is lacking is the will to put themselves at risk and this they are hesitant to do. They have an inherent cowardice when it comes to their own personal safety, and this can be exploited to advantage. Humans are inherently braver and in following divine inspiration are truly heroic. This the Anunnaki lack and it creates more of a level playing field than one might think.