Example https://jsfiddle.net/rost4719/1/

Works on desktop, but once switched over to mobile via the developer tool, it gets

Failed to load resource: the server responded with a status of 500 () chromewebdata/:1 Refused to display 'https://m.facebook.com/' in a frame because it set 'X-Frame-Options' to 'deny'. (index):2942 Uncaught TypeError: Cannot read properties of null (reading 'classList') at HTMLDocument.onDocumentLoad ((index):2942:19)

On PROD sites, it will also get CSP blockage since https://m.facebook.com was not used before for showing the embed therefore not configured as part of CSP.