I want to correct this, it is Bech32, also know that segwit wallet support both P2SH (compatible) and Bech32, but it does not support P2PKH (legacy) bitcoin address. But people like Bech32 bitcoin address because transaction fee is lower.
A "segwit wallet" doesn't "support" anything. There is no "segwit wallet".
Segwit is an improvement. And the address format is called bech32. That's the "real segwit".
Nested segwit is just P2WPKH nested into P2SH. That's not
really segwit but good for compatibility with outdated software.
I like bitcoin core too, it is a full client wallet, but not good for beginners as it needs more money space and subsequent backup of each addresses used to receive bitcoin [...]
You only need to backup your file once. Core uses HD wallets.
[...] it is a secret and safe wallet but the device used for it must be free of malware.
This applies to every desktop-, mobile-, browser-based- and web wallet.
As for me, I prefer electrum wallet just for the security sake.
Electrum is not more secure than core. That's a misconception you have.