Obviously this is in mental health. If you're self aware of how cynical you are (and believe me, I've also been there as I'm also in my 40s), you really should look for avenues of therapy that resonate with you. Someone to talk to could actually hash out some inner feelings and turmoil you might be holding on.
I am/was a people pleaser also. It's hard to not be nice when people ask but I also realize if I'm saying yes to someone, I'm saying no to myself or something that might be more important. It's good to at least weigh the balance that way.
My final suggestion is a tall order. It may or may not be a popular suggestion here, but I found that stoicism has helped me. I read, watch videos, and listen to podcasts about the ancient Stoics and it helps me deal with feelings and encounters that enhance those feelings. Getting road rage? Take a deep breath and forgive that person who cut you off. Everyone has their demons and misfortune and perhaps they needed it more. But the point is you take and keep control of your feelings and actions and then you'll pursue peace. Of course shitty things will happen in the world and you don't want to be callous about them. But once you keep your integrity, authenticity, and pursue wisdom, courage, justice and temperance, everyone will see that and follow suit.
Good luck, stranger. I'm just an idiot on the Internet but your words pulled on my heartstrings.
If you want some more reading material, check out Ryan Holiday. He's more modern oriented with stoicism. And of course YouTube or equivalent sources from him.