Here is a formal revision of the title:

Participation of Minister of Foreign Affairs Radosław Sikorski in the “The War for Minds: Fear, Subversion, Disinformation” Conference at the Sejm

Here are a few options, depending on where you want the focus to be:

Option 1 (Direct and professional): Developer of Fox River Resort Refutes Rumors of Exclusive Resort Policy

Option 2 (More formal/Journalistic): Fox River Resort Developer Denies Allegations Regarding Religious Exclusivity

Option 3 (Concise): Fox River Resort Developer Dismisses Claims of Religious-Only Development

Note: In a formal headline, it is generally preferred to use “refutes,” “denies,” or “dismisses” rather than “calls a lie,” as these words maintain an objective, journalistic tone.

Here are a few options for a formal title, depending on your focus:

Option 1 (Most direct and professional): “Resurgence of Online Disinformation Following President Zelenskyy’s Open Letter to Putin”

Option 2 (Focusing on the analysis): “An Analysis of Online Disinformation Trends Following the Zelenskyy-Putin Correspondence”

Option 3 (Concise and journalistic): “Online Disinformation Campaigns Intensify Following Zelenskyy’s Open Letter to Putin”

Recommendation: Option 1 is the most balanced and suitable for a formal news segment.