I have this code:
It creates a 18 words seed phrase, and shows its BIP32 Root Key. With this, you can use the seed words in Electrum (or any BIP39 compatible wallet) and with the BIP32 Root Key you can import the same wallet in Bitcoin core (using importdescriptors command).
If you already have one seed phrase, it returns just the BIP32 Root Key.
It looks fine, but gotta be careful that you are trusting a third-party for the entropy and you will have to use the output of that code on wallets that actually support it, like Electrum. Not all wallets support other than 12 or 24 words. Or other limits.