Engineering

As you have completed Diploma, you can also pursue B.Tech in regular mode rather than distance mode from best India's college like IIT government University central university private universities, as this type of degree has more value and also more chances to get job than distance type
IGNOU conducts admissions for B.Tech distance in two cycles January and July. Check website to stay updated about the July admission details for B.Tech course from IGNOU. You can apply for the course till the last date as based on IGNOU guidelines. Students can apply for various Bachelors, Masters, Diploma, postgraduate Diploma, and Certificate courses both programme and honours courses
The course fee of the whole B.Tech. Course at IGNOU is INR 20, 000. However, the fees may vary from specialisation to specialisation. IGNOU offers distance education at an affordable rate for the students who face financial instability and still wish to study from a recognised university. The course is offered in Construction Management and within that the student has to complete 2 modules in the course. After the completion of those 2 modules, the student will be eligible for the advanced construction management. The duration of general B.Tech is 4 years. However, the maximum duration to complete B.Tech. At IGNOU is 10 years. The specialisation that IGNOU offers in B.Tech is Construction Management which is a course that is made for working individuals. Hence, to let the working individuals have their time and a flexible routine, the university offers 10 years for the completion of the course. The course has 8 semesters with practical exposure as well.

JEE Mains score is used by various college for students to pursue B.Tech in different branches. Different types of colleges have their own criteria for admission
NIT IIIT recruit only on basis of JEE Mains, Central University government University takes admission based on JEE Mains or CUET
As your JEE Mains rank in ST category is under 20,000, you will allocated best NIT or iiit college, also you may allocated B.Tech in CSE branch from top NIT colleges
different NIT and iiit are best in different B.Tech branches, you should choose them wisely according to your desired branch. Here are top NIT and iiit college list
NIT DELHI
NIT CALICUT
NIT JAIPUR
NIT KURUKSHETRA
NIT TRICHY
NIT BHOPAL
NIT ALLAHABAD
IIIT HYDERABAD
IIIT ALLAHABAD
IIIT BHUVNESHWAR
IIIT LUCKNOW
IIIT MANIPUR
IIIT KARNATAK.

Yes you can give the JEE Advanced 2023 after qualifying the JEE Main 2023. The eligibility criteria is given below.
1. Age : The candidates should have been born on or after October 1, 1998. SC, ST, and PwD candidates are given five years age relaxation.
2. Number of attempts : A candidate can attempt JEE Advanced maximum of two times in two consecutive years.
3. Appearance in Class XII (or equivalent) examination : A candidate should have appeared for the Class XII (or equivalent) examination for the first time in either 2022 or 2023 with the subjects Physics Chemistry and Mathematics. Candidates who have appeared in the Class 12 examination for the first time in 2021 or earlier can also apply for JEE Advanced based on the special relaxation criteria.