RK-J

Current code is

<!-- Google Tag Manager -->

  <script>(function(w,d,s,l,i){

w[l]=w[l]||[];

w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});

var f=d.getElementsByTagName(s)[0],

j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';

j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;

f.parentNode.insertBefore(j,f);

})(window,document,'script','dataLayer','GTM-MHVNX9X');</script>

  <!-- End Google Tag Manager -->

Please replace with

<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-SJBX0M9032"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'G-SJBX0M9032');
</script>