ручний спосіб логування у файл

FileLoggerProvider.cs

// у чистому Microsoft.Extensions.Logging немає вбудованого файлового провайдера, але можна написати свій:

// Soccer.Infrastructure/Logging/FileLoggerProvider.cs

public sealed class FileLoggerProvider : ILoggerProvider
{
    private readonly StreamWriter _writer;
    private readonly object _lock = new();

    public FileLoggerProvider(string path)
    {
        Directory.CreateDirectory(Path.GetDirectoryName(path)!);
        _writer = new StreamWriter(path, append: true) { AutoFlush = true };
    }

    public ILogger CreateLogger(string categoryName) =>
        new FileLogger(categoryName, _writer, _lock);

    public void Dispose() => _writer.Dispose();
}

public sealed class FileLogger : ILogger
{
    private readonly string _category;
    private readonly StreamWriter _writer;
    private readonly object _lock;

    public FileLogger(string category, StreamWriter writer, object @lock)
    {
        _category = category;
        _writer = writer;
        _lock = @lock;
    }

    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
    public bool IsEnabled(LogLevel logLevel) => logLevel >= LogLevel.Information;

    public void Log<TState>(
        LogLevel logLevel, EventId eventId, TState state,
        Exception? exception, Func<TState, Exception?, string> formatter)
    {
        if (!IsEnabled(logLevel)) return;

        var line = $"{DateTime.UtcNow:O} [{logLevel}] {_category}: {formatter(state, exception)}";
        if (exception != null) line += Environment.NewLine + exception;

        lock (_lock) _writer.WriteLine(line);
    }
}

// і потім реєстрація в Program.cs:
// builder.Logging.AddProvider(new FileLoggerProvider("logs/app.log"));