Good morning dear HIVE and Dogecoin community !
You want to invest an important amount of money in the Crypto world ? Let's share some experience about crypto security, failures and good practices.
In the traditionnal banking system :
The crypto system is very rude, because in all the previous cases YOU are the ONLY responsible of YOUR funds:
But a major advantage of crypto world is also that YOU are the ONLY responsible of YOUR funds. You will not loose anything if your country currency crash or in case of bankrupt or even in case of war. And no one except YOU can access your funds or balance.
NOT your keys, NOT your coins
I wouldn't recommend to store your crypto on an Exchanges ... Why ? Simply because it anhilates the major advantage of the crypto due to KYC (know your customer) because everyone can associate your personal identity to your crypto funds and due to intermediate Wallets because if the Exchange bankrupts (or fly) then you may loose ALL your funds.
I would recommend paper wallet, you can create as many paper wallets you want, no need to register on an Exchange to generate a new one. It's like having several bank account numbers, you can have one for tips, one for storing your wealth, etc...
I would recommend installing a blockchain Core Node, because it allows you to manage your transactions yourself. If you do so, you become part of the blockchain, you lliterally become a bank operating transactions on the blockchain. Depending of your prefered blockchain, mine is Dogecoin and hosting a core node cost nothing (only 50 Go of space disk)
backup your wallet means store your private key + pub key + passphrase somewhere on a cold support (i.e: not connected), do not use a mobile or personal computer linked to internet to store your backup (to avoid hack). You can store it on a sheet of paper (i.e.: you print your private/pub key, passphrase) on few copies. Or you can store it on a simple USB key or external drive. Ensure to have redundant backup of your wallets, which means having multiple backups in case one is lost.
do NEVER communicate your private key or passphrase to ANYONE, even if he looks like an expert, a president or an angel.