Bitcoin does not have a security flaw which makes it susceptible to risks and attacks. What can happen is you as a user can have breaches in your device which exposes your personal wallet to risks, this is not a breach on the Bitcoin Network.
Protect your device from external threats by;
• Not clicking on untrusted links,
• No downloading random, unverified apps,
• Only use non custodian, open source and reputable wallets,
• Do not give third party access to your wallets,
• Use an airpagged device or hardware wallet.
If you have upgraded your cell phone then it's better to place your wallet on old cell phone which is no more required and keep it offline. This way you can have an air gaped device with zero investment.
Great list! I will add: keep the seed words offline, safely, without any chance for others to get access to them; the seed has to never touch a device that will ever go online. Keeping the seed as copies in multiple geographically distinct places is also a good idea.
Your seed is your wallet. Lost your seed, lost your coins. There is no way to recover your coins in case your seed is compromised or lose your seed. We can say that's one limitation of Bitcoin but we have to keep that aspect in our mind while designing the security architecture of our Bitcoins.