Unable to exercise pre-op

Normally I am a runner and keep myself in good health. At the moment I have plantar fasciitis and so haven't ran in about 2 months. My surgery is in 5 weeks and I'm just aware at the time I should be taking the best care of myself my fitness is at an all time low. Looking for a bit of reassurance that as long as I am in good health in general I will be okay? I've been trying to cycle/lift weights a bit more but am really unmotivated, running was my favourite exercise by far. That said I cannot wait to run in future without bowling balls attached to my chest 🤣.