Opensearch performance and throughput boundaries

I am trying to get an answer to how much event ingestions/ queries can be done on OpenSearch per unit time? As I am trying to use OpenSearch which will be shared among multiple users then it will be able to handle multiple requests/queries/operations at a single time? If yes what will be the limits, such that all things will work smoothly?

I would recommend you to take a look at Rally (GitHub - elastic/rally: Macrobenchmarking framework for Elasticsearch), it works with Opensearch clusters as well most of the time.

This will be very specific to the use-case. For example high-ingest rate logging has a completely different resource requirements than high-query load website search. You will need to share a bit more information about how the cluster will be used.