You can use mx-auto
on the col-lg-6
...
<div id="carouselContent" class="carousel slide col-lg-6 mx-auto" data-ride="carousel">
<div class="carousel-inner" role="listbox">
...
</div>
</div>
Also, it would be better to use w-50
instead of col-lg-6
since you're not using a grid row.
<div id="carouselContent" class="carousel slide w-50 mx-auto" data-ride="carousel">
<div class="carousel-inner" role="listbox">
...
</div>
</div>
Use negative margins to allow more room for the arrows...
<a class="carousel-control-prev ml-n5" href="#carouselContent" role="button" data-slide="prev">
<span class="carousel-control-prev-icon" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="carousel-control-next mr-n5" href="#carouselContent" role="button" data-slide="next">
<span class="carousel-control-next-icon" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
https://www.codeply.com/go/ZBwaLzuGT7