We had 6 camellias planted almost a year ago and they are looking very unhealthy. I've tried to figure out what is wrong with them from your article on diseases that affect camellias, but I'm unable to come up with a confident diagnosis and treatment plan. The buds are all brown and seem to be dead and many of the leaves have brown spots and, in some cases, half the entire leaf is brown. Let me know if you have any advice or if there is a way I can send a picture.
This sounds like a job for the Extension Service. This is a service run by your state dept of agriculture (and paid for by your tax dollars,) that offers free analysis of plant problems and advice on all things growing. This link will help you find one close to you: https://www.gardeningknowhow.com/extension-search/
Call them first to see what they recommend; usually they'll want to see leaf, flower, and soil samples.