I created a service that retrieves users from the database with a one-to-one relationship and so I have this ApplicationUser class

public class ApplicationUser
{
    public required int Id { get; set; }
    public required string Username { get; set; }
    public required string ProfilePicture { get; set; }

    public DateTime Created { get; set; } = DateTime.Now;

    public UserProfile? Profile { get; set; }
}

And this is the service function

public async Task<ApplicationUser?> GetByUserIdAsync(int userId, bool includeProfile = false)
{
    IQueryable<ApplicationUser> query = _dbContext.Users;

    if (includeProfile)
    {
        query.Include(u => u.Profile);
    }
    
    return await query.FirstOrDefaultAsync(u => u.Id == userId);
}

As you can see I added a argument includeProfile so that when I also need the user profile I can tell the function to include it.

The issue lies in the return type. Since ApplicationUser.Profile is nullable, when I access that property in my code even if I pass true for includeProfile, I get the warning that Profile could be null.

So my question is: How do I make it so that when includeProfile is true, ApplicationUser.Profile is not null?