Starting My Journey To Understand Blockchain

It's been a long time since I started observing the hype of blockchain, bitcoin, Ethereum, NFTs, etc. I couldn't help but wonder, it's just hyped it will be gone in no time, but it's still here. I thought I missed a lot, I could have learned and joined the hype and became a cool kid with NFT 😂. Jokes apart, the real reason I want to start with learning blockchain is to understand its architecture and how exactly this whole web3, the decentralization era is being utilized under the hood. I know nothing right now about what it exactly is, but I do have the following questions which I want to get answers of:

1. What is decentralization
2. How does this decentralization work, in case of no central server
3. How exactly does the communication happens
4. Since there is no central server, where does the data exist
5. If I am not wrong, decentralization can only exist when multiple nodes have data. In this scenario how is data secure
6. What is Web3 hype
7. How to write the backend for blockchain
8. How to create a client-side app for blockchain (web or mobile)
9. Can the existing software architecture and development concept I used for the last 5 years be used here?
10. What is an NFT?
11. How to create my own NFT
12. Can I really create the app shown in the silicon valley tv series 😆 , I know nothing about it
13. Is it really worth investing my time in it.
14. How can I connect what I am currently doing with the decentralization

I am thinking of following, the course by freecodecamp.org freecodecamp.org/news/learn-solidity-blockc..

Please provide me courses if any, I am excited to start the journey. I will try to provide insight into what I learned every day or every alternate day