Is it possible to change the shape of the buttons on the Owl Carousel?

Yes, you can include custom CSS that will change the original Owl Carousel buttons. You can do this by creating pseudo-elements ::before and ::after and adjusting styles as you want (dimensions, colors, arrow size, etc.).

The CSS below will change the buttons according to the styles defined. You will replace the original buttons with 50px buttons with a black arrow in the middle (see image):

  

Notethatsome!importantwasusedtooverridesome  settings.

<style>/*ajustoosbotõesnotamanhoqueeuquero*/.owl-prev,.owl-next{width:50px;height:50px;position:relative;background:none!important;}/*crioospseudo-elementos*/.owl-prev::before,.owl-next::before{content:'';position:absolute;top:0;left:0;width:100%;height:100%;background:red;border-radius:50%!important;line-height:50px;}/*hoverparamudardecor*/.owl-prev:hover::before,.owl-next:hover::before{background:aqua;}/*crioassetasecentralizo*/.owl-prev::after,.owl-next::after{content:"";
   width: 18px;
   height: 18px;
   position: absolute;
   transform: rotate(135deg);
   border: solid black;
   border-width: 0 3px 3px 0;
   top: 50%; left: 50%;
   margin-top: -9px;
   margin-left: -4px;
}

/* ajusto a seta next */
.owl-next::after {
   transform: rotate(-45deg);
   margin-left: -14px;
}
</style>