[Xylakant]

The courts disagree with you: https://www.kostenlose-urteile.de/LAG-Rheinland-Pfalz_7-Sa-3...

Note that in this case, additional infractions were committed, but the court specifically pointed out hat each infraction on it own would have been sufficient grounds for termination. And this was even without handing in a notice.

It’s certainly not the regular case that your employment will be terminated immediately for being late or not showing up once, but if you hand in your notice and don’t show up the next day without a damn good excuse, this will be treated as exactly what it is: cheating your employer for a wage. And that’s a standard ground for immediate termination.

Also note that just not showing up without a good cause entitles the employer to withhold your wage. So now you’re still employed, cannot take another full-time job and don’t get wage nor unemployment payments. Good way to footgun yourself.