But I also started to think twice about using Bitcoin Core because the synchronization process takes a lot of time.
Luckily, you only have to do that once. After that, is "only" downloads 11 GB per month at current rate.
It might be easier to use electrum.
Definitely!
Does using multiple USBs also require having bitcoincore data on each USB?
You only need to backup your wallet, not the blockchain. Worst case, you'll just download it again.
Actually electrum is very simple. One of the reasons why I want to use bitcoincore is because bitcoincore is a wallet created by satoshi.
Do you think both are equally safe? and can you explain a little about the advantages of electrum and bitcoincore?
From the point of view of the functioning of the Bitcoin network itself (its decentralization and security), it is preferable for users to use the Bitcoin Core wallet.
Because it is necessary to have a large number of full nodes in different parts of the globe, on different continents - this is the basis for the successful development of the Bitcoin network. And Bitcoin Core is exactly that wallet that allows you to create full nodes. Thus, by using the Bitcoin wallet - Bitcoin Core, you are contributing to the development of the Bitcoin ecosystem. At the same time, Bitcoin Core is very inconvenient to use compared to the lightweight Electrum wallet.
Bitcoin Core doesn't even support SegWit - this fact amazed me! That is, by using Bitcoin Core, users lose their money due to higher fees. At the same time, it cannot be said that Bitcoin Core is more secure than Electrum - it is not.
However, it is certainly much more difficult to use and requires very large computer resources.