I’ve heard that Nietzsche (who is often misquoted so I might be wrong here) said “what doesn’t kill you makes you stronger” so the pain you feel at the gym is only the pain that will make you stronger in the future. I don’t know if I’m doing Nietzsche justice but have a look into his stuff if you’re interested in the philosophy of leading a healthy life

I think stoicism a lot of value but is often misinterpreted by modern “sigmas” im not hugely educated on the topic tho. I personally try to be a virtuous person but I’m far from it with a long way to go. That aside I haven’t read Markus Aurelius this is just my surface level knowledge of the topic (which was discussed in a couple of classes that I didn’t really take notes in)

I’d read some Eckart Tolle. His book “A new earth: awakening to your life’s purpose” is a thought provoking text that talks about how we should have a different purpose to “hedonism” or “power” and argues the importance of spirituality (I haven’t finished it and I am slightly skeptical but it’s pretty interesting)

I don’t know if there are too many biology philosophers but you’d be best off looking at analytical philosophy and maybe philosophers who evaluate Charles Darwin. Hope this has helped

So sorta like - natural selection in the work place only the strongest get to high positions or something like that?

Not sure if this helps but I remember Simone de Beauvoir saying that biology was not essential in explaining “woman”. Whilst that first part of the novel is pretty hard to read it’s possible that she discusses it. That being said are you trying to argue that natural selection can increase the probability of survival?