There is a layout shift while the search input loads in. If performance can't be improved, consider adding a placeholder of the right dimensions to mitigate this and let users know what is happening.
https://www.figma.com/file/ejlKYV71qRFj8D6eQCwciM/New-docs-search-heuristic-evaluation?node-id=2-12822&t=qzQ6fAJCxhOTV728-4