I am already 46 years old and I stopped believing in “sounds too good” things ages ago… Especially regarding diets, they are famously overexaggerated. So you had your lesson. It’s individual and obviously so many factors are in play. Stress can mess up many things even some that may sound illogical.
True, people who got great results with keto (or IF) tend to talk about it like it surely brings quick, great positive changes to everyone. I don’t like that either but I understand those people to a great extent. And they are somewhat right, it works for many like that but not for everyone and it’s definitely not easy for everyone to stick to it anyway.
Articles, gurus, normal people: take their statements with a grain of salt and know that you are an individual, you can’t expect the same results as someone else or the average person.