Steven Phillips is a MD who became bedbound for 2 years. Fortunately for him, he was able to find a treatment that works and now works full-time as a doctor treating chronic illness and tick-borne diseases.
A good introduction to his ideas can be found on Dr. Been’s channel:
He believes that chronic illnesses are caused by bacteria, viruses, parasites, etc. transmitted by ticks, spiders, mosquitos, biting insects, etc. Unfortunately, these microbes are difficult to detect with medical tests. The treatments aren’t that great because what works for one patient may not work for another. However, with enough time and experimentation, he claims that the majority of his Lyme+ patients are able to regain most of their normal life. (Some of his patients stop seeing him, e.g. because it isn’t working, so that may make his statistics better than they are.)
A few of his claims don’t fully line up with the scientific literature. He claims that all autoimmune disease is caused by infection and doesn’t mention how diet treats celiac disease. But that’s a little nitpicky on my part.
You can also read his book Chronic, available where books are sold (e.g. Ebay, Amazon).