2. If someone has compromised your iCloud account and/or device, you have bigger things to worry about
3. No
Yes and no according to Glenn Fleishman. Storing FileVault recovery keys in iCloud Keychain wasn't a choice before. The old iCloud recovery method wasn't end to end encrypted. But iCloud Keychain is. So calling it escrow is debatable. And old recovery keys aren't added to iCloud Keychain. But new recovery keys are stored in iCloud Keychain if enabled.[1]
[1] https://sixcolors.com/post/2025/09/filevault-on-macos-tahoe-...
FWIW and having not looked yet (since I never upgrade major macOS versions anymore without a good 3-5 months going by and the first 2-3 minor fixes first) my default assumption is it's still possible to not escrow recovery keys, if only because plenty of people don't use iCloud keychain at all (including myself), and also because I know for sure that you can use configuration profiles to control FV recovery key escrow already. That'd be a requirement for lots of business usage so even if it needs a profile to use should still be there? But again this all seems orthogonal to the issue at hand. Stuff does crash or need updates that require a reboot and previously you either needed to turn off FV entirely or use a hardware workaround for GUI access (ie, setup a basic SBC with HDMI/USB in and use it as a bridge or use a premade solution along the lines of PiKVM [0]). It's definitely a small but nice (and feels rare nowadays from Apple) remote admin gesture to let it be done in software like it should have been long ago.
----
2) copy unencrypted SSH host key from it to a new computer (which necessarily must not be stored in the data volume), configured with the network identity of original computer
3) leave new computer in place of original to capture remote SSH-to-unlock attempt
4) use knowledge of password to unlock original's filevault at your leisure somewhere offsite
iCloud Keychain is NOT the same security as a hardcopy written down recovery key, which is what I used before. This is absolutely a forced change in security policy that was not communicated or opted into by the user.
At least if you have an iCloud account attached to your profile (I have no idea what happens if you don't), the upgrade process will automatically and without notification or asking consent add your recovery key to the iCloud Keychain. It does tell you afterwards what it so helpfully did.
That doesn't mean all my security should be a house of cards with a single point of failure in the form of my iCloud account and/or device(s). Someone shouldn't be able to get the keys to the castle just by compromising any single one of those.