Ummm... Reddit is not a "cash cow" - quite the opposite, Reddit bleeds money. But, overall that's not impacting your question one way or the other.

Both of your points are way over-the-top and unnecessary to discredit Lemmy. They certainly don't have to even touch Lemmy itself, they simply have to leverage their own platform and their own userbase to circulate negative views of Lemmy and keep people coming to Reddit. They also don't have to pay news agencies - users seeking trusted media is no longer a thing in a world of social media; some clickbait articles on crap websites are all that's needed and those will be distributed (and redistributed) for free if they're jucy enough to attract readers.

Some attack avenues which come to mind:

• Maxist-Lenonist roots of Lemmy itself, along with digging up the backgrounds of various admins around the world and posting wild accusations of their moral character
• Lack of moderation and circulation of far right-wing and left-wing theories
• The structure/reliability of federation. Volunteers running servers which talk to each other, you sign up with one server and who knows if it'll stick around; and if it does disappear suddenly, then you have to join a different instance and start all over again.
• Conspiracy theories on how/why Lemmy instances are funded. Secret funding from Chinese/Russian governments looking to subvert "the west" through social media? Collecting "dontations" to run Lemmy and diverting the money in support of terrorism?
• Small userbase and relatively small amount of content compared to the vastness of Reddit
• Lack of centralized contact for legal issues - from takedown notices for copyrighted content to privacy to right-to-be-forgotten legislation. And, sooner or later, there will be revenge porn and *sigh* child porn popping up. Federation is going to multiply the issue as posts are propogated and many dozens/hundreds of admins will have to be contacted to take action.
• Your entire post history is open to all - whether it be for training AI, to someone looking to scam you, to governments of the world keeping a close eye on you.

But, to be honest, Reddit doesn't have to do any of that to maintain their position at the top of the heap. All they really have to do is look internally and stabilize Reddit. Remove Spez and replace him with someone who can build a vision and knows how to communicate. Spend money on their own app to make it usable and accessibilty-friendly. Spend money on a marketing head (and team) who can create a workable/profitable advertising program. Probably, they'll have to shrink down Reddit's scope and remove the NSFW subreddits, figure out a way to deliver ads to all users, and adjust costs for "premium"/ad-free experience and API access to roughly equate with with revenue they would have received serving ads. If Reddit puts a new CEO in place and announces the vision for the future withing six months and implement the changes within another six months, they'll likely keep 85% of their existing userbase.