This Pro tutorial provides the steps to update the text of a sticky div with the title of the post that is hovered on the Posts page in Bricks.
Step 1
Create a Page named say, “Blog” and set it as the Posts page at Settings → Reading.
Edit it with Bricks.
Copy this JSON of the Section and paste.

Step 2
Click on Settings (gear icon) near the top left → PAGE SETTINGS → CUSTOM CODE → Body (footer) scripts:
<script>
document.addEventListener("DOMContentLoaded", () => {
// store the text of #post-title-holder
let postTitleHolderText =
document.querySelector("#post-title-holder").innerText
// loop through each .blog-post
document.querySelectorAll(".blog-post").forEach((post) => {
// when the post is hovered, set the value of its data-title attribute as the text of #post-title-holder
post.addEventListener("mouseover", () => {
document.querySelector("#post-title-holder").innerText =
post.getAttribute("data-title")
})
// when the post is no longer hovered, set the text of #post-title-holder to whatever was there before
post.addEventListener("mouseout", () => {
document.querySelector("#post-title-holder").innerText =
postTitleHolderText
})
})
})
</script>