Bip39 offline https://zanevnex175.lowescouponn.com/practical-use-a-python-based-bip39-seed-generator-in-the-real-world Despite the fact that it utilizes BIP32 strategy you may continue to import BIP39 seeds into Electrum wallet. Also other than BIp32 You can find BIP44 Model which some wallet use for your era of seeds. The amount of safety does a passphrase incorporate? A BIP39 passph... https://linktr.ee/bip39