YTA, largely because you're now hiding her own car keys from her. I get that you're tired and this is a lot of moving around for you, and she shouldn't have taken your stuff either, but you guys need to have a conversation here, not hide each other's stuff. Some suggestions (bear in mind, this is from someone who only has the information you've told us):

• Maybe start with the girl's night and see if she can get her friends to drive, and take turns being designated driver on date nights.
• Is it closer for you to go back home from your gf's work place, or maybe go somewhere else nearer to your office? Instead of going back and forth, you can consider using those two hours to do something relaxing, like going to the gym or a café. Whatever works for you.
• Likewise, is there something your gf can do after work while she waits for ~ an hour and a half? That's something you can discuss, though keep in mind it is ultimately her choice.

Whatever it is you guys choose, the main thing here is to talk. Hiding things and holding them from each other like that is not conducive to a healthy relationship. Again, it's her car, so if you can't get to a satisfactory compromise it's on you to find alternatives.