JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/OwlCarousel2/2.3.2/assets/owl.carousel.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/OwlCarousel2/2.3.2/assets/owl.theme.default.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/OwlCarousel2/2.3.2/owl.carousel.min.js"></script>
<div class="owl-carousel owl-theme">
    <div class="item"><h4>1</h4></div>
    <div class="item"><h4>2</h4></div>
    <div class="item"><h4>3</h4></div>
    <div class="item"><h4>4</h4></div>
    <div class="item"><h4>5</h4></div>
    <div class="item"><h4>6</h4></div>
    <div class="item"><h4>7</h4></div>
    <div class="item"><h4>8</h4></div>
    <div class="item"><h4>9</h4></div>
    <div class="item"><h4>10</h4></div>
    <div class="item"><h4>11</h4></div>
    <div class="item"><h4>12</h4></div>
</div>

CSS

.opacity {
  opacity: .2;
}

JavaScript

$('.owl-carousel').owlCarousel({
    loop:false,
    margin:10,
    nav:true,
    responsive:{
        0:{
            items:1
        }
    },
    onChange: callback,
})

function callback(event) {
		console.log($('.owl-carousel .owl-item'))
		var sbAllItms = $('.owl-carousel .owl-item').length;
    if(event.page.index==-1){
    	console.log('убираем ', sbAllItms-1)
    	$('.owl-carousel .owl-item').eq(sbAllItms-1).removeClass('opacity');
    }else{
    	console.log('убираем ', event.page.index)
    	$('.owl-carousel .owl-item').eq(event.page.index).removeClass('opacity');
    }
    console.log('добавляем ', event.property.value)
		$('.owl-carousel .owl-item').eq(event.property.value).addClass('opacity');
}