The most recent version of Debut successfully updates variants on inputs with the class name single-option-selector. I have working radio buttons based on a metafield ( product.metafields.product_selector.type == 'radio' ). No need for js customizations. Just customize how it looks with css, but don't use css to target the single-option-selector class.
{% unless product.has_only_default_variant %}
<div class="product-form__controls-group">
{% for option in product.options_with_values %}
{% assign i = forloop.index %}
{% assign i0 = forloop.index0 %}
{% if product.metafields.product_selector.type == 'radio' %}
<fieldset class="product-form__controls-group"
id="SingleOptionSelector-{{ i0 }}"
>
<legend>{{ option.name }}</legend>
{%- for value in option.values -%}
{%- assign variant_label_state = true -%}
{%- if product.options.size == 1 -%}
{%- unless product.variants[forloop.index0].available -%}
{%- assign variant_label_state = false -%}
{%- endunless -%}
{%- endif -%}
<input type="radio"
class="single-option-selector single-option-selector-{{ section.id }} product-form__input"
{% if option.selected_value == value %} checked="checked"{% endif %}
{% unless variant_label_state %} disabled="disabled"{% endunless %}
value="{{ value | escape }}"
data-index="option{{ i }}"
name="{{ option.name | handleize }}"
id="SingleOptionSelector-{{ option.name | handleize }}-{{ value | escape }}"
>
<label for="SingleOptionSelector-{{ option.name | handleize }}-{{ value | escape }}">
{{ value }}
</label>
{%- endfor -%}
</fieldset>
{% else %}
<div class="selector-wrapper js product-form__item">
<label for="SingleOptionSelector-{{ i0 }}">
{{ option.name }}
</label>
<select class="single-option-selector single-option-selector-{{ section.id }} product-form__input"
id="SingleOptionSelector-{{ i0 }}"
data-index="option{{ i }}"
>
{% for value in option.values %}
<option value="{{ value | escape }}"{% if option.selected_value == value %} selected="selected"{% endif %}>{{ value }}</option>
{% endfor %}
</select>
</div>
{% endif %}
{% endfor %}
</div>
{% endunless %}
