"Instructs the browser to use the fallback font to display the text until the custom font has fully downloaded. This is also known as a “flash of unstyled text” or FOUT."
not sure if i want a flash of unstyled text
i believe you can just use this custom css in lay options -> custom html&css:
body{
font-display: swap;
}
that should work and this way your change in the php file wont be overwritten when you update lay theme next time
