Filtering related models using django-filters?

Question

Django

There are two related models

class Skill(models.Model):
    """Information about an employee's skills."""

    LEVELS = (
        ('basic', 'Basic'),
        ('intermediate', 'Intermediate'),
        ('advanced', 'Advanced'),
        ('expert', 'Expert'),
    )

    YEAR_CHOICES = []
    for r in range(1, 11):
        YEAR_CHOICES.append((r, r))


    employee = models.ForeignKey(
        Employee, on_delete=models.CASCADE, related_name="employee_skills")
    technology = models.ForeignKey(Technology, on_delete=models.CASCADE)
    year = models.IntegerField(verbose_name='Duration of technology use (years)', choices=YEAR_CHOICES, default=1)
    level = models.CharField("level", max_length=64, choices=LEVELS)

    def __str__(self):
        return '{} is {} in {}'.format(
            self.employee.full_name, self.level, self.technology.name)

class Project(models.Model):
    """Project information."""

    name = models.CharField("project name", max_length=64)
    description = models.TextField("project description")
    technologies = models.ManyToManyField(
        Technology, verbose_name="technologies used on the project")

    def __str__(self):
        return self.name

filters.py

class EmployeeFilter(django_filters.FilterSet):
    skills = django_filters.ModelChoiceFilter(queryset=Technology.objects.all())

    class Meta:
        model = Employee
        fields = ['skills']

template.html

<form method="get">
            <div class="card-body">
              <div class="row">

                  <div class="form-group w-100">
                    <label for="skills">Technology</label>
                  {% render_field filter.form.skills class="form-control bg-light" %}
                </div>  
       
              </div>
              <button type="submit" class="btn btn-warning">
                <span ><i class="fas fa-search"></i></span> Search
              </button>
              <button type="button" class="btn btn-secondary"><span ><i class="fas fa-recycle fa-fw"></i></i></span><a href="{% url 'account_list' %}" class="text-white">Clear</a></button>
            </div>
          </form>

In this form, the search by skills works, i.e. I get filtered users with selected values ​​from the Technology model, but I also need to extract level from the Skills model, and that’s the difficulty. The user model contains an association with the Technology model

class Employee(models.Model):
    """Employee information."""
    user = models.OneToOneField(
        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='employee')
    skills = models.ManyToManyField(
        Technology, through="Skill", verbose_name="skills", blank=True)

How to reach the value of the required field in Skills?