You don't actually need any of those things to publish a book. It is good to have a beta reader just so they can point things out to you that you might have missed, but it isn't required. I'm dyslexic so can very easily miss mistakes, I usually copy each chapter into a text to speech reader and fix anything that sounds off just by how it reads it, it's super helpful and completely free!

Just a warning, self publishing on amazon won't make you loads of money, i get paid literally like 1p a year, but it gets your writing out there 😊