I have created an application customizer extension and put my custom header and footer in that extension which loads fine. I had to hide the OOTB ribbon and left bar as I wanted to have totally customized look.
Everything is working fine, however when I load the page, at first it shows the SharePoint Online OOTB items and then when the extension loads it removes these and shows my header, footer and other components. This is what I see when the page loads first. After that, it loads my custom stuff.
Question: Is there any way to avoid this flicker or jitter effect? Can I hide these and show a blank page before my components get load?