Polytechnic

B.Tech/BE through distance will be the best for you as you already have 6 years of work experience. Distance B.Tech degree along with your work experience will prove beneficial for you in the future.

You will get admission in DTU through LEET only when you process the 3-year Diploma result in front of DTU LEET committee.

Hello Atharva,
If you intend to get admission in an IIT then the answer is yes. This is so since IIT's treat Diploma as equivalent to 12th and hence you can appear for JEE Mains and JEE Advanced for admission. However, if your intention is for lateral admission then you will have to go through matrix of eligibility versus possible branches of engineering, available on website of DTE of Tech Edu Maharashtra.

All you need to do is write the diploma CET entrance exam and with a good rank, you are eligible for lateral entry.

Polytechnic after 10th can be good as you can get direct second year entry into engineering colleges through the LEET exam. But, I would prefer you to go with regular 11th and 12th because it will give you better options for appearing in engineering entrance exams.
Hence, if you plan to pursue engineering in the future, then go for regular 11th & 12th otherwise opt for Polytechnic.

No need for a separate preparation.
Just be sure about your basics and revise your school concepts.
It's quite enough to score high, which gives you a seat in top colleges for your Polytechnic.

Group 'H' Syllabus:
For this group, the syllabus is divided into five sections that are Reasoning and Logical Discussion, Numerical Ability and Scientific Aptitude, English and General Knowledge. Intermediate level questions will also be asked. Regards.

Hello Atul,
For getting admission in any college, you have to appear in CLAT exam and on that basis, you can get admission in any college.

Yes, it's a great option and also, I would suggest you to go for certification courses. Talking about government jobs, you can get a government job in their cyber security departments.