Although you're won't be expected to build a blockchain from scratch, you need to be skilled enough to handle the duties of blockchain development. You need to have some fundamentals in data structures, cryptography, and networking and distributed systems to learn blockchain properly.
Here are the technical fundamentals:-
1.) Try to Understand What is Data structures
The complexity of blockchain requires a solid understanding of data structures. At the core, a distributed ledger is like a network of replicated databases, only it stores information in blocks rather than tables. The blocks are also cryptographically secured to ensure their integrity every time a block is added.
Cryptography has been derived from two Greek words (Kryptos & Graphite) which means secret writing. Cryptography is a method used to secure information and communication through the use of mathematical principles by encrypting a message so that only the intended receiver can read it.
3.) Decentralized applications
Decentralized applications (DApps) are software built on blockchains. As a blockchain developer, there are several platforms where you can build a DApp.
In the modern lifestyle, learning blockchain dev is not difficult just you need to read all the basics to become an expert.
The banking sector, the insurance industry, governments, and retail industries are some of the sectors where blockchain developers can work. If you're willing to work for it, being a blockchain developer is an excellent career choice! Hope it helps!