According to a CNN report, this claim is credible. Although there are no sources linked in the original Bluesky post, upon searching the web for this topic, I came across one main article, the CNN report, that seems to be the origin of this claim. It mentions how, "a document produced by the Naval Criminal Investigative Service said the intelligence community assessed with 'high confidence' that foreign adversaries were trying to recruit federal employees and 'capitalize' on the Trump administration’s plans for mass layoffs". Although this document and other government sources mentioned in the article were not able to be accessed, the breadth of information that CNN covers in the article backs it up well. In addition, the CNN article and others like this one from The Independent emphasize how these claimed recruitment efforts just make sense - federal employees who may be bitter from being fired could be the perfect targets for gaining info on another country; the CNN article even says, "the CIA also aggressively seeks to recruit disaffected government employees in adversarial countries 'all the time'". The CNN article also confirms the use of LinkedIn as is mentioned, and includes the fact that TikTok, RedNote and Reddit could be used as well.
Unfortunately, the only great source on this issue is the CNN article, but from what I can see, other sources aren't available to be accessed because they are government documents. Based on this article, then, the claim is true.