Either looks fine. Make sure you know how far a reach it is back into the corners, since it seems there isn’t room for pop up access like George showed in your return loop plan.
I know, it’s always something!! 🤪 In my plan I can reach the corners because I don’t have track too close to the open operating area. We went over and over plans just to get my simple plan to work out.
Also think about how to access lower level track with the upper track in place, and how you will support the upper track with lower tracks in the way. Two sides of the same coin. Also think about overhang clearances with curving adjacent tracks. The lower right looks a little close.
All that said, you are thinking outside the box. I think you need to with O gauge in a small room. I have a hard time thinking outside the box.