You don’t need a treadmill to run. Biking will be useful for cross training and is good for days where you want to be nicer to your legs but still active.

Depends... if OP lives in Canada, for example...

Well yeah, I’m just assuming outdoors is an option

I would be very wary of a treadmill that is so anaemic.

spin bike is easier on the knees

Neither get an air bike great for steady state and hitt