JSFiddle - React, Tailwind, and code Playground

HTML

<button onclick="myForwardFunction()">Forward</button> 

  <button onclick="myBackFunction()">Back</button> 


  <section>
    <svg viewBox="0 0 240 200"><path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="lightgrey"/></svg>
    <div id="pathed" class="pathed"></div>
  </section>

CSS

section {
  width: 244px;
  height: 200px;
  border: 2px dashed lightgrey;
}
body {
  display: flex;
  padding: 10px;
  flex-wrap: wrap;
  gap: 30px;
  margin: 0;
  height: 100vh;
  justify-content: center;
  align-items: center;
}

div {
  width: 50px;
  height: 50px;
  border: 1px solid hsl(343,100%,58%,.3);
  border-right: 5px solid hsl(343,100%,58%);
  background: hsla(343,100%,58%,.3) radial-gradient(circle, hsl(343,100%,58%,1) 3px, hsl(343,100%,58%,0) 3px);
  display: flex;
  justify-content:center;
  align-items: center;
  font-family: monospace, sans-serif;
}

.pathed {
  offset-path: path('M0,0 C40,240 200,240 240,0');
  position: absolute;
  animation-play-state: paused;
  animation-direction: normal;

}
@keyframes distance_1 {
  from {
    offset-distance: 0%;
  }
  to{  offset-distance: 100%;}
}

@keyframes distance_2 {
  from {
    offset-distance: 100%;
  }
  to{  offset-distance: 0%;}
}

code {
  position: absolute;
  top: 100px;
  right: 10px;
  left: 10px;
  line-height: 1.5; 
}
section {
  position: relative;
}

* {
  box-sizing: border-box;
}

svg {
  position: absolute;
  opacity: .333;
  stroke-width: 2px;
}

JavaScript

function myForwardFunction() {
      document.getElementById("pathed").style.animation = "distance_1 4000ms alternate ease-in-out";
      document.getElementById("pathed").style.animationDirection = "running";
      document.getElementById("pathed").style.animationFillMode = "forwards";
    }

    function myBackFunction() {
      document.getElementById("pathed").style.animation = "distance_2 4000ms alternate ease-in-out";
      document.getElementById("pathed").style.animationDirection = "running";
      document.getElementById("pathed").style.animationFillMode = "backwards";
    }