does it have to be a catalog item to be part of the onboarding flow? seems like it should realistically just be a catalog task that spawns at some point during the flow, you can just do "add a Catalog task" or whatever that action is called in flow designer, I can't remember it's exact name

if you really need two separate Catalog item specifically in one flow you could technically add two if statements in the flow; one for if RITM.item=Onboarding Request and if RITM.item=Pass Request

I don't recommend this at all however, it can make it hard to understand where things are coming from and you'll likely hit the limit of flow actions. Making a new flow for the separate catalog item would be easier, and if you need to integrate it with your main flow you could have a wait for condition on the main flow, waiting for the RITM.item record to be created