Have a 2022 Forester which has different starlink computer display screens than the Outback, but I had a somewhat similar thing happen a few weeks ago. On startup the starlink screen displayed the icons it normally does, but I could not press any icons, nor adjust volume on radio/SiriusXM, nor see backup camera in reverse. Tried turning off engine and restarting right away and did nothing. luckily, the AC direction/speed buttons are all hard buttons in the Forester (which changes in the new 2025 one) so I could adjust that. Drove home with radio real loud. Turned off engine again and restarted it; same problem. Waited about 10 minutes, restarted car and everything was fine again. Problem never happened again, so I can not bring it in for service since there is nothing wrong that I can show the dealership. No outstanding recalls and I assume you have no outstanding recalls or software updates that need to be done?
The Starlink electronic display screens are one weak point of a lot of newer Subaru's, but unfortunately, they just keep putting more and more functions in the computer display. I prefer old fashion hard buttons for controls so you can feel for them and not take eyes off the road while driving. BUT, guess that is just me.
Guess the next time this happens, if you have the time, you just have to drive straight to closest Subaru dealership without turning off engine and say .... SEE this is my problem, but it may or most likely may not happen after I restart the car another day!