There is a rather simple means to have a secure hardware wallet, and it works far better than Ledger or Trezor and those sorts of wallets. In this post I will discuss this using an Android Samsung, as this is what I use, but similar processes are available on most phones.
An old phone is a good wallet. It can be a new phone, but an older model can also work.
On a Samsung phone, there is a “work mode” where the section is encrypted. This allows for apps with a biometric and second-layer encryption.
Using a wallet such as Centbee, where you hold your keys, you can move your Bitcoin onto the phone and leave it off when not in use.
If you do not use the phone for browsing and email etc., the attack surface is extremely small. Most attacks are going to be client-side. You do not even require the phone to have a SIM, as it can connect to wireless only (making it even more secure).
Personally, when compared to the existing “hardware wallets” and the security they offer…
I would recommend the SIM-less phone.