There are a couple of things that you can use to get alerted on OOM and other issues, one is certainly container_oom_events_total which is provided by cadvisor but it has an issue when using it alongside Kubernetes see open GH issue here. You could also use kube_pod_container_status_last_terminated_reason{reason="OOMKilled"} but then again it's not entirely accurate because it doesn't clear until a container is terminated for a different reason meaning it might be running and instead return such data. Last but not least you could use node_vmstat_oom_kill which as of today is working as expected, the downside of this one is that it works at node_level meaning it will not trigger only for a specific pod but for any pod having OOM issues (if you ask me this is good enough for alerting, regardless of it is a specific workload or not you want to get alerted when OOM its happening).

But if you need to use something that will give you the specific workload you could use a group_left between the kube_pod_container_status_restarts_total and the kube_pod_container_status_last_terminated_reason which should give you the restarts caused by OOM per workload... Something like the query below

sum by (namespace, pod) (kube_pod_container_status_restarts_total) * on(namespace, pod) group_left(reason) kube_pod_container_status_last_terminated_reason{reason="OOMKilled"}