I could live on 50% my salary now -- after building my retirement funds. I'm probably a lot older than you are. I'm not married. In Germany if this matters.
Progressive taxation and health insurance costs help a lot. You'll earn half the brutto, but the interesting question is the netto. You can run your numbers here: https://www.brutto-netto-rechner.info/teilzeit.php (in German)
1400 net can be a perfectly liveable depending on location / housing cost, but you need to think about retirement savings!