An excellent effort using some complex and compound sentences! Here are a few more suggestions. In 2017, when I left university because I didn't like majoring in chemical engineering, I decided to take a gap year to discover which major I preferred. Since March 2019, I have been taking English classes to improve my English skills and support my future career in which I have not yet found employment. Hope this helps

AFTER I LEFT UNIVERSITY IN 2017 BECAUSE I DON'T LIKE MY MAYOR IN CHEMICAL ENGERNEERING. I DECIDIED TO TAKE GAP YEAR TO FIND OUT WHAT MAYOR I LIKE. IN MARCH 2019 I TOOK A ENGLISH CLASS TILL NOW TO IMPROVE MY ENGLISH SKILL AND SUPPORT FOR MY FUTURE CAREER SO I STILL HAVEN'T APPLIED FOR ANY JOB YET Corrected version: After I left university in 2017 because I DIDN'T like my MAJOR in chemical engineering, I decided to take A gap year to find out what MAJOR I like. In March 2019, I took AN English class UNTIL now to improve my English skill and SUPPORT MY future career so I still haven't applied for A job yet.

Can I write it in any better way?