Running is not just a sport but a biological necessity.
It is as if I can see my body in front of me.
When one runs 45, 50 or even 100km, for me, is not an ultra runner
My advice is that you should use your brains more and train less.
Like a tree that grows stronger with more branches and roots, you need to find more and more ways to be inspired.
Without patience, you will never conquer endurance.