We haven’t even fully grasped the system of self-propagating chemical reactions that increasingly met more criteria of “life” before a single cell was formed. Everything suggests that the process is super rare so it’s safe to assume it only happened successfully once. Tectonic plate movement has erased geologic evidence of conditions around the origin of life but given that all known forms of life share the same basic elements (H, C, N, O) and reactions, it is harder to argue against a single origin than for it.