This has been asked about before (mostly for cycling, e.g. What about my outdoor rides? or XP point for outdoor rides), and doesn’t normally find much support.
But if you really do want to accumulate Zwift XP/distance while running outside, you can do that. You just need to take your phone along and run Zwift while you’re running. I used to do it while paired with my Stride pod. It worked well, although it drains the battery quite quickly.