TinyMCE sizing properties needed

I have a text field for the user to enter big chunks of HTML code. On the form this field shows up with the top menu and then only 3-4 lines available. Any ideas how to make the space for the text make taller (i.e 80+ lines), so when the text is pasted most of the lines are immediately visible, without any user interaction.

echo <<<HTML
<script>
	document.addEventListener("DOMContentLoaded", function () {
		const interval = setInterval(() => {
			const editorBox = document.querySelector(".tox.tox-tinymce");

			if (editorBox) {
				editorBox.style.height = "400px";
				editorBox.style.minHeight = "400px"; // opcional pero útil
				clearInterval(interval);
			}
		}, 200);
	});
</script>
HTML;