Esta é apenas uma das muitas formas de criar #buttons circulares com #bootstrap .

 

 

circle button bootstrap 5

 

Código do exemplo

<!DOCTYPE html>
<html lang="en" dir="ltr">

<head>
 <meta charset="utf-8">
 <title>bootstrap 5 - botões circulares</title>
 <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3" crossorigin="anonymous">
 <style media="screen">
 .my-circle-button-1 {
 width: 50px;
 height: 50px;
 }

 .my-circle-button-2 {
 width: 100px;
 height: 100px;
 }

 .my-circle-button-3 {
 width: 200px;
 height: 200px;
 }
 </style>
</head>

<body>
 <div class="container mt-3">
 <div class="container">
 <div class="row g-3">
 <div class="col">
 <button type="button" name="button" class="btn btn-secondary border-dark text-center rounded-circle my-circle-button-1 m-0 p-0">100</button>
 <button type="button" name="button" class="btn btn-info border-primary text-center rounded-circle my-circle-button-2 m-0 p-0">100</button>
 <button type="button" name="button" class="btn btn-info border-danger text-center rounded-circle my-circle-button-3 m-0 p-0">100</button>
 <button type="button" name="button" class="btn btn-danger border-secondary text-center rounded-circle my-circle-button-3 m-0 p-0">100</button>
 <button type="button" name="button" class="btn btn-secondary border-dark text-center rounded-circle my-circle-button-1 m-0 p-0">100</button>
 <button type="button" name="button" class="btn shadow btn-warning border-warning text-center rounded-circle my-circle-button-2 m-0 p-0">100</button>
 </div>

 <div class="row g-3">
 <button type="button" name="button" class="btn btn-danger border-secondary text-center rounded-circle my-circle-button-3 m-0 p-0">100</button>
 <button type="button" name="button" class="btn btn-light shadow border-dark text-center rounded-circle my-circle-button-1 m-0 p-0">100</button>
 <button type="button" name="button" class="btn shadow btn-success border-white border-3 text-center rounded-circle my-circle-button-2 m-0 p-0">100</button>
 </div>
 </div>
 </div>
 </div>

</body>

</html>