These guys not only directly placed a hundred-billion bounty on the deep web for Li Pan's head, soliciting the entire mercenary groups in Night City to attack Panlong. They also rallied a huge bunch of riffraff and losers locally, supplying them with guns and cannons to send over for harassment. It's like they're saying, "I might not be able to beat you, but I sure can disgust you."
Fortunately, Li Pan has a bit of a reputation in Night City as well. It wasn't his first time having a bounty of over billions on his head. Veterans like the Iron Queen, well-versed in the cyberpunk world, knew that corporate wars were deadly and stayed well away. As for the lawless underworld of Night City, those slightly formidable ninja assassins and gangsters had already been preemptively wiped out by Li Pan, leaving a void of manpower. At the moment, there really wasn't any particularly formidable character who could threaten him.