How can I add inline markup to submit buttons?

I migrate code from Drupal 7 to Drupal 10, in Drupal 7 I often created buttons with an icon and text like showen aboven:

Drupal 7 code:

$form['submit'] = [
  '#type' => 'submit',
  '#value' => t('<i class="glyphicon glyphicon-share"></i> Register'),
  '#attributes' => ['class' => ['btn-success btn-sm']],
];

When I try to do this in my drupal 10 code, the icon (I replaced the glyphicon by a bootstrap icon and the icon is showen when I use it e.g. in #markup) is not visible. I recognized, that drupal 10 renders '#type' => 'submit' as <input> instead of <button> and I think that this is the reason for this behaviour.

(Not working) Drupal 10 Code:

$form['actions']['submit'] = [
  '#type' => 'submit',
  '#value' => Markup::create('<i class="bi bi-box-arrow-up-right"></i> Register'),
  '#attributes' => ['class' => ['btn-success btn-sm bi bi-box-arrow-up-right']],
];

I was really wondering why this is so complicated in D10, I thought this would be a common task. Is there perhaps a simple option that I missed or has anyone a suggestion how I can add icons to the text of submit buttons like I did it in Drupal 7?

Thank you for your ideas.

One possible solution (as showen in the link of @Clive) might be using a html <label>.

The following works for me:

$form['actions']['submit'] = [
  '#type' => 'submit',
  '#prefix' => Markup::create('<label for="edit-submit" class="btn btn-primary"><i class="bi bi-box-arrow-up-right"></i> Register</label>'),
  '#value' => 'Register',
  '#attributes' => ['style' => ['visibility:hidden']]
];

The drupal created button will be hidden and replaced by the label, the drupal submit handler will still be called.

This is the sort of customisation best done in the theme, and fortunately there's a neat little trick that will help you achieve it, using the '#theme_wrappers' key:

$form['actions']['submit'] = [
 '#type' => 'submit',
 '#value' => $this->t('Register'),
 '#theme-wrappers' => ['input__submit__register_button'],
];

With this setting in the button array the theme layer will, before using the default suggestions, look for a template called 'input--submit--register-button.html.twig', which might contain something like this:

<input{{attributes}}><i class="bi bi-box-arrow-up-right">{{children}}</i>

This technique extends to other elements though for some you will need to use the '#theme' key rather than '#theme_wrappers', and some experimentation may be necessary. (Note that '#theme' expects a string value rather than an array.)