Entity Framework Core: different threads using the same instance of DbContext

The application was developed on ASP NET Core 3. To log user actions, I decided to use a single method in the Project class. Faced the problem of using one singleton dbContext from different threads.

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    string connection = Configuration.GetConnectionString("ConnectionDB");
    services.AddDbContext<DataBaseContext>(options => options.UseSqlServer(connection), ServiceLifetime.Transient, ServiceLifetime.Singleton);

    services.AddSingleton<Project>();
}

Project.cs

public async Task AddUserLog(string action, string message, int userId)
{
    try
    {
        UserLog userLog = new UserLog()
        {
            Action = action,
            Message = message,
            UserId = userId
            Datepoint = DateTime.Now
        };

        _dbContext.UserLog.Add(userLog);
        await _dbContext.SaveChangesAsync();
    }
    catch (Exception ex)
    {
        await AddSystemLog("Project", "AddUserLog", ex.Message);
    }
}

SchemeController.cs

public class SchemeController : ControllerBase
{
    private readonly Project _project;

    public SchemeController(Project project)
    {
        _project = project;
    }

    [Authorize(Policy = "AdvancedControl")]
    [HttpPost("[action]")]
    public async Task SomeMethode()
    {
        for (int i = 0; i < 10; i++)
        {
            await _project.AddUserLog("Text", "Message", 42);
        }       
    }
}

Already at the second iteration of the loop, I catch an exception in the AddUserLog method: "A second operation started on this context before a previous operation completed. This is usually caused by different threads using the same instance of DbContext."

I suggest several solutions:

1. Add the log to the buffer table and then save it to the database by timer. But this is not the best way out;

2. Block the method while it is being saved to the database.

But I don’t like any of the options.

Please tell me the correct approach in solving this issue.