@azb1 as a developer I will say that no wallet is fully secure, you have more and less security based on how they work but even hw are not fully secure. Also your keys could be in a server and still be non-custodial depending on how it works.
Being honest number 2 and 3 are impossible to prevent if you are the target of a good attack and the wallet has bad security practices. For example if the wallet you are using isn't well protected to XSS attacks then even if you only download the wallet from the official source and your computer is not infected with malware, hackers can still take the seed from your wallet without you ever notice it. Even without the need of a hacker involved there has been bad practices from wallet creators where they even have logs for development purposes which by definition should never be in a wallet but yet we see them and an old massive hack with a Solana wallet was an example
I would never care about number 1 btw, people who are always making a big deal about it are just not looking where they need because if lets say pbkdf2, sha256 hashes and AES get broken because of quantum computer... Your bitcoins are the less important thing you should care about. This is similar to those saying the dollar and banking system imminent doom: In such situation there are more important things than where you buried your gold bars.
The safest way known today are hardware wallets, ledger being the safest one today.
PS: You also need to have good practices about how you backup your mnemonic phrase