Typically unlocking the bootloader requires a full wipe. It’s a security method intended to keep an attacker from compromising your OS to access your data if the phone is stolen.
I’ve never rooted a phone without requiring a wipe, but I’ve owned mostly Samsung
Even old Samsung phones would let you root and flash custom roms without wiping, the bootloader was open from the factory and you could just override your recovery and system partition with Odin. That’s how I did it with my Galaxy Gio during the Android 2.2 days
Typically unlocking the bootloader requires a full wipe. It’s a security method intended to keep an attacker from compromising your OS to access your data if the phone is stolen.
I’ve never rooted a phone without requiring a wipe, but I’ve owned mostly Samsung
Even old Samsung phones would let you root and flash custom roms without wiping, the bootloader was open from the factory and you could just override your recovery and system partition with Odin. That’s how I did it with my Galaxy Gio during the Android 2.2 days
I’ve owned pixels and Nexus and you could unlock without wipe. Locking required a wipe. Now both do not sure when it changed though.