Convert model method to eloquent relationship

Schema::create('users', function (Blueprint $table) {
    $table->id();
    $table->foreignIdFor(Task::class)->constrained();
});

Schema::create('tasks', function (Blueprint $table) {
    $table->id();
});

class User extends Authenticatable
{
    public function tasks(): BelongsToMany
    {
        return $this->belongsToMany(Task::class);
    }
}

class Task extends Model
{
    public function users(): HasMany
    {
        return $this->hasMany(User::class);
    }

    public function latestUser(): HasOne
    {
        return $this->hasOne(User::class)->latestOfMany();
    }

    public function oldestUser(): HasOne
    {
        return $this->hasOne(User::class)->oldestOfMany();
    }
}

class Task extends Model
{
    public function users(): HasMany
    {
        return $this->hasMany(User::class);
    }

    public function latestUser(): ?User
    {
        return $this->users()->orderBy('users.created_at', 'desc')->orderBy('users.id', 'desc')->first();
    }

    public function oldestUser(): ?User
    {
        return $this->users()->orderBy('users.created_at', 'asc')->orderBy('users.id', 'asc')->first();
    }
}