What theme are you using? Normally you can just set a static front page in the Dashboard -> Appearance -> Customize. Though the theme will have to support a static front page. You have to make a brand new page for the front page, and you then fill that with content, before selecting it to be the front page in the customize screen. You can have a separate page if you want for blog posts. Key thing is the front page becomes a page, that's fixed content, rather than a dated blog post.