Polytechnic

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.

List of Top Polytechnic Colleges in India
Government Polytechnic, Mumbai
S H Jondhale Polytechnic
V.P.M.'s Polytechnic
Vivekanand Education Society's Polytechnic
Adesh Polytechnic College
Anjuman Polytechnic
Agnel Polytechnic
Chhotu Ram Polytechnic
Adhiparasakthi Polytechnic College
MEI Polytechnic
Government Polytechnic
Nanda Marga Polytechnic
Seth Jai Parkash Polytechnic
AANM & VVRSR Polytechnic
Andhra Polytechnic

Hello Bharat, I feel you should bid for admission in an engineering college after your 12th. Every state has good colleges. In addition there are some private Universities also where you can seek admission. So start preparing for CET of your state.