To disable linking from the post title and featured image you may add the CSS provided in this article to the Divi Theme Options.

For this, go to Divi >> Theme Options in the WordPress dashboard menu. Now stay in the General tab and scroll to the bottom of the settings to paste this CSS code.

/* Divi Blog Extras - Disable All Links */
.el_pb_blog_extras a,
.et_pb_post_extra a {
    pointer-events: none !important;
    cursor: default !important;
}

Element-Specific Code

 
/* 1. Post Title Link */
.el_pb_blog_extras .entry-title a,
.et_pb_post_extra .entry-title a {
    pointer-events: none !important;
    cursor: default !important;
}
/* 2. Featured Image Link */
.el_pb_blog_extras .entry-featured-image-url,
.et_pb_post_extra .entry-featured-image-url,
.el_pb_blog_extras .post-media a {
    pointer-events: none !important;
    cursor: default !important;
}
/* 3. Read More Button Link */
.el_pb_blog_extras .more-link,
.et_pb_post_extra .more-link,
.el_pb_blog_extras .ajax-more {
    pointer-events: none !important;
    cursor: default !important;
}
/* 4. Meta & Category Links (Author, Date, Category) */
.el_pb_blog_extras .post-meta a,
.et_pb_post_extra .post-meta a {
    pointer-events: none !important;
    cursor: default !important;
}