You should ask this, but maybe hold back on the “I abhor it” stuff.
While for some places it may even be a good sign you want Linux, serious rejection for other platforms may look like a lack of flexibility. Who’s to say you don’t have the same strong feelings about other stuff?
Trust your manager and the people who hired you. They picked your for a reason. Sometimes it’s not what you think makes a good employee in this position, but something much more specific to the team or situation you’re in. If in doubt: Ask!
Many times people who come straight from uni don’t feel productive enough, because they can’t be productive for 8 hours straight. But that’s normal. Staring at the ceiling blankly on occasion is normal too. If you’re doing your best and the matter you’re working with is working well for you, then you’re very likely fine.
There’s always a bit of impostor syndrome in all of us, but still try to get comfortable and trust your colleagues. Ask for feedback from your superior, if you’re unsure.