It sounds like you want to switch to the OBS Studio App so you can switch scenes, etc.
You can use Automator to create a custom service to launch the application of choice and bind a global keyboard shortcut to do so.
- Open Automator, select New Document and Choose Quick Action (Service)
- In Workflow Receives (Service Receives) drop-down list select No Input
- Drag Launch Application from the Actions list to the right side
- Select the OBS App as the Launch Application
- Save the Automator Quick Action (Service) as "Launch OBS"
- In System Preferences -> Keyboard -> Shortcuts -> Services scroll down and find Launch OBS and set a keyboard shortcut for it.
This will open OBS and bring up the minimized window and it will unhide it as well.
There's a great deal of potential solutions that may be even more useful in controlling OBS. If you rethink your workflow a bit, the deeper problem is controlling OBS while you are streaming or recording. OBS has a websocket API and can be remotely controlled via a web browser but it can also be remotely controlled via iOS/iPad Apps as well as actual hardware controller boxes (stream deck or MIDI controller) with a myriad of programable buttons and dials to control OBS and a lot more. You can add an inexpensive second monitor, even an old iPad setup as a second monitor and put OBS on the iPad.