Advanced tip is to remove the derailleur hanger and see against a flat surface wether it’s straight or not. If not, and you don’t have the calibration tool then just clamp it on a vice and use hammer/pliers/crecent wrench to bend it back straight. It’s not going to be perfect but since it’s already bent you’re probably not going to make it worse either.
Back in the days only people with a strong will to survive did, infact, survive and the genes from those people are in all of us. Many like to pretend they don’t posses these features but that’s only because you’re living a modern comfortable life, so you never need to rely on it. Especially compared to what it would’ve been 10k years ago.
You can take any modern man, and put him along with his family in a house and place an angry stranger pounding at the door shouting threats at his wife and kids and you’ll soon discover the violence you just thought wasn’t there.