The Tailwind bg-gradient-* class applies a linear gradient (in this instance) similar to the CSS code below
background-image: linear-gradient(to bottom right, #67e8f9, #3B82F6, #8B5CF6);
When using hover:bg-slate-200, only the background color changes while the background-image remains unchanged. To achieve the desired effect, adjustment of the background-image is necessary.
To override the background-image property, first set hover:bg-none
<!DOCTYPE html>
<html>
<head>
<script src="https://cdn.tailwindcss.com"> </script>
</head>
<body>
<button class="rounded-full bg-gradient-to-br from-cyan-300 via-blue-500 to-purple-500 hover:bg-none hover:bg-slate-200">
Hire Me
</button>
<! exactly reversing -->
<button class="rounded-full bg-gradient-to-br from-cyan-300 via-blue-500 to-purple-500 hover:from-slate-200 hover:via-slate-200 hover:to-slate-200">
Hire Me
</button>
</body>
</html>