A lot of people think 2FA is 100% safe, It is not. Hackers can call up your phone companies and steal your sim card and number, some can spoof your own number. Do not have faith in 2FA on exchanges, it has been proven it is not safe 100`s of times now. I believe the best way to store bitcoins may be a hotwallet with a password mixer on your own computer not attached to the internet, but I think cold wallets may be good to. Sure some 2FA`s help, but it is not 100% secure. You probably want to use Linux to, not windows or apple shit or whatever horrid OS your phone is running on.
As proven in the case of the Binance hack, the 2FA security platform is not anymore safe as hackers have already gotten the advanced steps that can be taken to counter this option. This is the reason why some are already talking about 3FA but of course this can be the necessary burden we have to take just to feel that we are secured. Sadly, hackers are ahead of the game and with the resources they already hoarded and the technologies at their disposal, I am sure that hacking will be here to stay and they can be successful with rich targets from time to time. Exchanges should always be on guard as hackers are just waiting to make a big strike anytime.