It's safer to use a real BIP39 seed created elsewhere if you really need Nested SegWit addresses in Electrum.
There are many bitcoin wallets that are open source that can be used and this is what I would have gone for which is easy.
Generating it on Sparrow wallet will be good. There are other wallets that can be used for it like Passport if it is for airgapped. Or other wallets like Bluewallet, Unstoppable if it is on mobile.
Cold wallets are the safest but off-topic to tthis discussion.