1. Use a non-custodial wallet to protect your Bitcoin portfolio.
Yes, it is not all non-custodial wallets that are worth it (an example is Trust Wallet, which i see now as a shit wallet) for the protection of our Bitcoin holdings.
For adequate protection, verify the downloaded wallet before imediately after download before using it.
2. Store your security key and seed phrase in multiple secure locations so that you can recover your Bitcoin if your device is lost or stolen.
Yes, but it has to be in an offline location.
3. Send a small amount of Bitcoin to verify that the wallet address is correct.
4. Avoid using QR code scans to protect yourself from fraud.
No, that is incorrect. In addition to being safer against clipboard hijackers, using a wallet QR code scan to obtain the recipient wallet address relieves you of the burden of confirming the recipient wallet address.