Don't ask me why I don't store in exchanges because I trust myself more than exchanges.
(Reference: Coincheck suspended withdrawals.)

I have a pair of Trezor, and a pair of Ledger Nano S, but there are a lot more altcoins that can't be stored within these hardware wallets.
For example, I have XVG, ADA, IOTA, XMR, and etc.

They do have an open-sourced wallet, do you install them into your "alternative" desktop/laptop with virtual windows separating each of them to ensure maximum security?