var fmResultIds = fmResultset.Resultset.Records.Select(r => r.Fields.First(f => f.Name == primaryKeyName).Value).ToArray();
switch (config.Value.GetTableName())
{
    case "FmCompanyIntegration1":
        // The FMCompanyIntegration1 should be a parameter
        var allsql1 = context.Set<FmCompanyIntegration1>()
            .Where(t => true)
            //The issue here, the primary key should be a parameter
            .Where(t => fmResultIds.Contains(t.CoId))
            .Take(100000)
            .ToDictionary(kvp => kvp.CoId, kvp => kvp);
        //this is taking care to update/insert the record. We do not have to delete anything
        foreach (var record in fmResultset.Resultset.Records)
        {
            var entity = allsql1.FirstOrDefault(r => r.Key == record.Fields.First(f => f.Name == primaryKeyName).Value).Value;
            if (entity != null)
            {
                // LoadRecord is not a problem, because all entity is comming from the same base class, which has this function defined
                entity.LoadRecord(record);
                context.Entry(entity).State = EntityState.Modified;
                updated++;
            }
            else
            {
                // here I also have to dynamicaly create the class...
                entity = new FmCompanyIntegration1();
                entity.LoadRecord(record);
                context.Entry(entity).State = EntityState.Added;
                inserted++;
            }
        }
        break;

    // full copypaste from above. I would like to get rid of this obviously
    case "FmBookBackyard1":
    default:
        var allsql2 = context.Set<FmBookBackyard1>()
            .Where(t => true)
            // Again I know what is the primary key field name... Or I am ready to extend any reasonable class to give it back
            .Where(t => fmResultIds.Contains(t.BkRecordId))
            .Take(100000)
            .ToDictionary(kvp => kvp.BkRecordId, kvp => kvp);
        //this is taking care to update/insert the record. We do not have to delete anything
        foreach (var record in fmResultset.Resultset.Records)
        {
            var entity = allsql2.FirstOrDefault(r => r.Key == record.Fields.First(f => f.Name == primaryKeyName).Value).Value;
            if (entity != null)
            {
                entity.LoadRecord(record);
                context.Entry(entity).State = EntityState.Modified;
                updated++;
            }
            else
            {
                entity = new FmBookBackyard1();
                entity.LoadRecord(record);
                context.Entry(entity).State = EntityState.Added;
                inserted++;
            }
        }
        break;
}
context.SaveChanges();