Contrarian

A person who is constantly looking for an argument or conflict is often referred to as a "contrarian." A contrarian is someone who deliberately opposes or disagrees with others, even if their viewpoint is not necessarily based on strong reasoning or evidence.

Other terms that might apply, depending on the context, include:

𝗔𝗿𝗴𝘂𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝘃𝗲: Someone who is prone to engaging in arguments.
𝗖𝗼𝗻𝘁𝗲𝗻𝘁𝗶𝗼𝘂𝘀: A person who tends to provoke or stir up conflict.
𝗕𝗲𝗹𝗹𝗶𝗴𝗲𝗿𝗲𝗻𝘁: Someone who is hostile and eager to fight or argue.
𝗣𝗼𝗹𝗲𝗺𝗶𝗰𝗮𝗹: A person who engages in controversial debate or disputes, often in an aggressive or combative manner.

The behaviour is typically driven by a desire to challenge or provoke rather than to seek constructive dialogue.