Secure storage

Hello everyone, recently I have bought some Ethereum and wanted to buy more but I cant bring myself to trust these exchange platforms to keep them there.

So I researched about it and the best way to store your crypto is through "cold wallets"

But with cold storages you have types either a keystore file or mnemonic phrase and "hardware wallets"

I know hardware wallets are a good option but I found out there is fraud within that category as well.

My current way of saving is through paper wallet mnemonic phrase that I open only through Tails operating system which I've installed on a USB and I boot that whenever I want to do any transactions.

I want to keep my crypto for the long term.

How can I make this even more secure? Is my way secure enough?