You can add this script in your custom page node to hide the header and footer
Run on Enter
<script>
document.getElementById("header-editor-preview").style.display = "none";
document.getElementById("footer-editor-preview").style.display = "none";
document.querySelector(".header-container").style.display = "none";
document.querySelector(".footer-container").style.display = "none";
</script>
Run on Exit
<script>
setTimeout(() => {
document.getElementById("header-editor-preview").style.display = "block";
document.getElementById("footer-editor-preview").style.display = "block";
document.querySelector(".header-container").style.display = "block";
document.querySelector(".footer-container").style.display = "block";
}, 500);
</script>
See example decision tree here: