It's great that you're considering moving your BTC from an exchange to a more secure offline storage solution. I think you should consider ,Wallet Seed Backup

Writing down or engraving the seed phrase on steel is a secure way to back up your wallet. It's crucial to store this backup in a safe and accessible location.
While Electrum currently uses a BIP39 seed, potential changes in standards may impact its compatibility in the future. Storing the master private key as a QR code can be an alternative, but ensure you keep it secure and prevent unauthorized access.

In all, prioritize security, accessibility, and future-proofing when selecting a storage solution for your BTC. Consider your preferences, concerns, and the potential adaptability of the chosen wallet to ensure you can access your funds securely in the years to come.