Instead of pace, now power should be target in pace pro strategy. Why isn't it there yet, is native running power in garmin 255 still not reliable?
Pace pro gives you the pace, in order to run a specific distance knowing if you are ahead or behind a target pace and by how much.
What you are looking for is Training/create new training/run/ select the run part(you can just modify or create a new one), at the bottom of the page you can se t the activity goal with the power target you want to keep during the run.