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Insert button under Checkout button

Add to Home > Settings > Advanced > Code Injection > Footer

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.0/jquery.min.js"></script>
<script>
  $(document).ready(function() { 
    $('<button class="sqs-editable-button CheckoutButton-checkoutButton-3yWY2 checkout-button">New button</button>').insertAfter('.CartFooter-checkout-28MW2.checkout');
  });
</script>