How to use ChoiceField and ModelChoiceField with allauth Templates?

Based on the default allauth Templates I want to build a Custom SignUp Form which also includes ChoiceField and ModelChoiceField. Therefore I did the following adjustments:

accounts/models.py

class Country(models.Model):
    name = models.CharField(max_length=20, unique=True)

    def __str__(self):
        return self.name

class CustomUser(AbstractUser):

    SALUTATION = (
        ('m', _('Mr')),
        ('f', _('Mrs')),
    )

    salutation = models.CharField(
        max_length=1,
        choices=SALUTATION,
        blank=True,
        null=True
    )
    country = models.ForeignKey(
        Country,
        on_delete=models.PROTECT,
        verbose_name=_('Country'),
        blank=True,
        null=True
    )

accounts/forms.py

class CustomSignupForm(forms.Form):
    salutation = forms.ChoiceField(widget=Select, choices=CustomUser.SALUTATION, initial=CustomUser.SALUTATION)
    country = forms.ModelChoiceField(queryset=Country.objects.all(), initial=Country.objects.all())

templates/allauth/elements/field.html

{% load allauth %}
{% if attrs.type == "select" %}
    <select name="{{ attrs.name }}" id="{{ attrs.id }}" class="form-select mb-3">
        {% for option in attrs.value %}
            <option value="{% if option.0 %}{{ option.0 }}{% else %}{{ option.id }}{% endif %}">
                {% if option.1 %}
                    {{ option.1 }}
                {% else %}
                    {{ option }}
                {% endif %}
            </option>
        {% endfor %}
    </select>
{% elif attrs.type == "checkbox" or attrs.type == "radio" %}
...

Options only get populated to attrs.value when passing 'initial' parameter in the form. Shouldn't this be provided by 'choices' or 'queryset' parameter instead? Is there an option to get the values from attrs object in a different way?

class CustomSignupForm(forms.Form):
    salutation = forms.ChoiceField(
        widget=Select,
        choices=CustomUser.SALUTATION,
        initial=CustomUser.SALUTATION,
    )
    country = forms.ModelChoiceField(
        queryset=Country.objects.all(),
        initial=Country.objects.get('United States'),
    )

class CustomUserCreationForm(forms.ModelForm):
    salutation = forms.ChoiceField(widget=Select(attrs={'placeholder': 'Salutation'}), choices=CustomUser.SALUTATION)
    country = forms.ModelChoiceField(widget=Select(attrs={'placeholder': 'Country'}), queryset=Country.objects.all())