Extract an Excel in background (for large files)

Is it possible to insert cron job logs inside the database? So we can check it in our Admin Panel?

Yes, of course.

You can create your own format that you are comfortable displaying in your own special dev dashboard controller, or you can just record event and keep it in DB and then browse with PHPMyAdmin or something if you want to.

I find log files a bit easier personally, but I'm not doing any log analytics per say (ie taking data and making graphs or anything like that), but it's completely up to you