Yes, Book for 2, pick up either from entrance or bar and proceed.
I never had any problems, at one instance the lady arrived earlier than I reached reception, when I emerged from the lift she was already in front of lifts, greeted and took the lifts .. the reception desk was manned and near the lifts and no intervention from their side,
If it's too late they may lock the main door and only ones with card access can walk past the main door..so I that case you need to go past reception to main door and provide access to the lady

Yes your overthinking it
Always Book the hotel room for 2 just in case
Then meet your ‘partner’ at the bar and go upstairs to the room together