With Patreon you can just set up one tier and use it for general support. That's all I have officially set up on mine right now, as I don't have enough of a back log to offer anything else. You can offer as little or as much as you want with each tier and 'general support' is an option. I recommend both Patreon and Ko-Fi. I've set up both but haven't really had time to optimise them yet.
I've noticed that the people who make the most on Patreon are those who offer early pages/chapters. Which is why I personally want to build up a back log of edited chapters I can offer. I just plan to post early chapters and maybe exclusive short stories that aren't relevant to the main plot so my readers who can't afford to support me won't miss out on anything. If you’re worried about excluding readers that’s the most common way, I’ve seen it used by other creators on this website.