Bin into fitness nowadays, did some 10km fun runs and now want to go into half marathon.

But somehow my apple app keep showing my vo2 max is only 27.
But treadmill and indoor cycle show my range around 41-43.
So i want to really improve my vo2 max on apple app by deciding to jog /run outdoor.
Can recommend good our door running shoes and model?

Ended up buying cumulus 25. novablast3 a bit hard on the insole and is foam only.
Nimbus25 feels a bit unstable, maybe because too high and extra squishy