Your summary of the iCloud route is right, and it is worth tightening two details because they decide whether it works at all.
iCloud.com > Find My > Erase This Device requires that Find My iPhone was enabled before the lockout. If it was, the erase works remotely, no cable needed, and the phone restarts to setup. If Find My was off, the device will not appear in the list and this route is closed — that is the most common reason people report "the erase button is missing".
The part your post leaves out is what happens after the erase: Activation Lock asks for the Apple Account that was previously signed in. Erasing does not remove that requirement in any iOS version. So the iCloud route gets you a clean phone only if you also control the Apple Account. If the account is locked out too, you are in Apple's account recovery flow (iforgot.apple.com), which can take days, or you need Apple Support with proof of purchase.
If Find My was off, recovery mode is the fallback: Mac Finder or Windows Apple Devices, forced recovery button combo, then Restore. Same Activation Lock rule applies. And if the phone shows "Security Lockout" with an Erase option on-device (iOS 17+), that is quicker than either — it accepts the Apple Account password directly on the lock screen.
Worth adding for anyone reading later: a "passcode bypass" that claims to preserve data on a locked iPhone is always misrepresenting what it does. Apple has no API for that, so the only outcomes are erase-and-restore or a hardware intervention that damages the device.
For families with mixed devices, the iPhone side is best kept on Apple's native controls (Screen Time, Family Sharing), while Android, Windows and Mac machines can be managed from one dashboard — that is the coverage Ultimate Phone Spy provides (plans).