I didn’t specifically test the 2K doorbell, but all the rest of their cameras wipe when synced.
If someone just steals the device and doesn’t sync it while in range, then you should be able to view the older clips from that device. They may get cleaned up by some process if the device never connects again. They will get wiped by the 90 day limit Eufy implemented last year without telling anyone, but that applies to any saved video from active cameras as well.
If someone makes off with your doorbell, I would immediately download any critical clips just to be safe.