I understand you have two requirements:
- Scale the request process to work among multiple departments
- Create events on department calendars for approved requests
Yes, this is possible, but you will need to modify the Flow template to get the desired result. Fortunately this is fairly simple and only requires a few additional actions.
Also, if you are going to use this Flow with a large population, be cognizant of the number of Flow runs you have in your tenant. If you go over your allotted quantity of runs then the flow will stop working until the next billing cycle.
Anyway, to create events for approved requests on multiple department calendar, you will need some way to look up the location of each calendar by department name. So you may need to create, for example, a lookup list in SharePoint to match department names to site URL's & list names, etc.
(In the Flow you would put these actions inside the If yes branch of the condition.)
The department of the user who made the request is automatically supplied by Flow, so all you have to do is use a Get Items action and Filter on that value:
After this action you can use values from the lookup in subsequent actions.
If your department calendars are in SharePoint Online then you would want to use the Create Item action, and then fill in the details of the event under Advanced Options.
If instead you use Exchange to host department calendars then you would use the Create Event (V2) action instead.
In either case, you must make sure that the user account that authorizes these action also has sufficient access to all department calendars, wherever they are. You can find which account is associated with each action by clicking on the ellipsis in the upper right corner of the action:
