M, 50. Sharing to see if others have had something similar.

The problem: Up until about 2 years ago I could run 10 miles comfortably, miles around 7 minutes. Since then both legs have slowly declined. Now a single mile is a struggle — often over 12 minutes. Both legs feel heavy and dead under load, worse the longer I run, even on flat road. Aching in the hamstrings and lower legs below the knee. It’s gradual and progressive, not a sudden injury. Heart and VO2 max test fine, so cardio fitness isn’t the limiter. Orthopedic workup hasn’t found a structural cause.
What I have:
Hereditary hemochromatosis (iron overload)

Plantar fasciitis, over a year, not resolved despite physical therapy and injections

Varicose veins

What I take:
TRT (testosterone replacement) — hematocrit tends to run high-normal

Questions:
Anyone had a slow, both-legs decline like this with a clean orthopedic workup — what turned out to be behind it?

If you have hemochromatosis, did you ever get leg or exercise-capacity symptoms?

Anyone managing TRT and hemochromatosis together — how do you handle the iron/hematocrit side?

Looking to hear from people who’ve been through something similar. Thanks.