Should I join an online course from Coursera/Udemy etc to become a better problem solver while making logics during code writing.. or what should I do to improve this issue… I am very very worried about my future?

Take an algorithms course.

The one I would recommend if you’re really struggling is the fourth edition of Robert Sedgewicks ‘Algorithms’, because it uses actual code implementations rather than pseudocode. It’s pretty short compared to other algorithms textbooks but it goes over everything you absolutely should know to be a serious programmer. The material in this book is available as a MOOC thanks to the University of Princeton, and they even have a free Coursera course to go along with which I highly recommend. Everything can be found here:

Algorithms, 4th Edition

However, no algorithms textbook will prepare you to solve problems intuitively, you can only achieve this by… solving problems.

HackerRank and Leetcode are good websites to use since they have a strong focus on coding interview preperation. Alternatively, you can also try AlgoExpert, I’ve personally not tried it myself but I’ve heard overwhelmingly positive things about it. I’d say pick one of the three above and stick to it.

If you’re struggling even with the material above, I’d guess your weakness is in discrete math. In which case, you need to brush up on your maths, specifically algebra, number theory and/or combinatorics. If it’s your programming ability, then I’d suggest you go over to one of my previous answers.