To be able to achieve your aim…
example…
let myString = "Hello WORLD !!!";
$w('#text1').html ="<h1 style='color:#F43F63; font-family: Futura,Trebuchet MS,Arial,sans-serif; font-size: 30px'><mark>${myString}</mark></h1>";
Define COLOR, TEXT-SIZE, TEXT-STYLE like you want.