I am using this little fella to realize such things: https://github.com/adnanh/webhook
It is basically a little webhook server you can run on windows and send webhooks to it from Homey.
I primarily use it to shutdown all my systems but you can basically call any command with it.
For the PC side you just need to grab this webhook executable and set up your commands in this hooks config file. It is rather well documented on the github wiki I liked you.
The only problem you will really face is how to trigger the commands on the PC. So you need something which can be executed on the PC side to do the trick.
Alt+F9 sounds like nvidia
I think the webhook utility cannot direclty issue a keypress. But it should be possible to call a utility from it to mimic that keypress. Maybe have also a look at autohotkey regarding that. That’s another popular utility.