You are right, even my 80%+ funds are on centralized exchange, but that's on purpose. I cannot buy Cold wallets in my country as crypto is banned but arrangements can be made but I don't want to take the risk. Waiting for it to be unbanned again and then I might consider buying one.
This is simply calling for trouble, you don't have to buy a hardware wallet in that case, you have the option to use Electrum offline, by creating your own airgapped wallet.
I was also going to mention it as we can use paper wallet to but I avoid it, it is so difficult for me to carry or safe a paper wallet, I don't have any someplace in my home where I can keep it away from others hand. And there are other reasons too so I avoid it but a air gapped wallet can do the work instead.
I don't think stompix was talking about a paper wallet, but rather that you use a self custodial wallet like Electrum that gives you your seed phrase, which you have to back up on paper. Not your keys, not your coins, to use BTC you must find a way to back up your seed phrase safely, it should be easy to write 12 words down and hide it somewhere.