The general rule is that as you go up in elevation, so does the price for identical units. Ground floor units can be more appealing than garden units but they still are not as sought after by buyers. To entice a buyer you have to price it lower than other 2 Br units. So long as you do your homework and don't pay the same price for an identical unit on the 2nd floor, you'll see a resale value in line with the market for such units.
Good luck, Ken.
This value can be measured by reviewing all past sales in the building and surrounding buildings which your buyer's agent should provide to you. On the other hand, mitigating circumstances would be a larger outdoor space as you have noted. Good luck!