Why did Abraham Lincoln personally remove so many commanders in charge of the Union army during the war?

Abraham Lincoln frequently removed commanders of the Union army due to their perceived incompetence and inability to achieve decisive victories, which frustrated his strategy for winning the Civil War. He sought leaders who could effectively execute military campaigns and utilize resources efficiently. Lincoln's persistent adjustments aimed to enhance morale and effectiveness within the Union forces, reflecting his determination to secure a swift end to the conflict. Ultimately, his decisions were driven by the urgent need for competent leadership in the face of a protracted and bloody war.