AsyncTransaction.cs

using (var tran = await _dbContext.BeginTransactionAsync())
{
    try
    {
        var modelsToRemove = await _dbContext.QueryModels
            .Where(f => /* some filter here  */)
            .ToArrayAsync();
        if (modelsToRemove.Any())
            _dbContext.QueryModels.RemoveRange(modelsToRemove);
            
        // remenber to call SaveChangesAsync() after every write in order to
        // ensure that the operation has been performed.
        // The Ef DbContext is not thread safe and if there are multiple instances of the
        // service, data might not be persisted correctly.
        await _dbContext.SaveChangesAsync();
        
        if (newModels?.Any())        
            _dbContext.QueryModels.AddRange(newModels);        

        await _dbContext.SaveChangesAsync();

        tran.Commit();
    }
    catch (Exception ex)
    {
        tran.Rollback();
    }
}