I am making this post to share a terrible experience of victim who lost $2m over a simple act of negligence or rather carelessness. I will say he played with $2m that is supposed to be saved a cold wallet that is disconnected from the internet.
This lesson is not new and recommendation for safety repeatedly said on the Internet.
If you have $2M in capital, you should never store all $2M in a single wallet.
Split your capital ($2M) to different wallets, hot wallet, cold wallet, single signature wallet, multi-signature wallet.
Split your capital and wallet on different devices.
The bottom line, and is vital, don't explore new platform, new smart contracts, with a wallet in which you store big capital. What is big capital?
What you see fit, $2M or $1M or even just $20,000.
For new things (projects, platforms, smart contracts), explore them with a small wallet.
Remember to revoke smart contract approval after you done.
How to revoke Token Approval.
https://etherscan.io/tokenapprovalcheckerhttps://revoke.cash/https://app.unrekt.net/