I'm not sure if a Ledger hardware wallet comes with a Bitcoin wallet pre-installed. If it needs the Ledger Live software, it may still work if you install that on an offline system.
I wouldn't worry about firmware updates for a device that never sees the internet.
Ledger is always changing shit around but I think they are now shipping wallets (from China) without any preinstalled apps but they are suggesting that you can install Bitcoin and other apps.
That means it's not possible to use it in offline computer, and I wouldn't even do that when there is Electrum wallet.
I did try installing Trezor Suite offline on Linux and it's working just fine, you only need to enable Bitcoin (or other supported coins) but you may need to install other software needed for app to run.
I guess there's not really a market for it, because it's not very convenient to use, but I'd like to see a hardware wallet that's truely designed to be used offline. It could for instance use a camera (or QR-code on it's screen) to transmit transaction data, and instead of USB use only a power cable. That way, you could have a hardware wallet that's also a cold wallet.
Keystone hardware wallet is designed to be used offline and they are using QR codes for sending transactions.
You can also make your own airgapped signing device using Raspberry Pi zero (version without wifi).