Camelia problem, help!

Hi all, I’ve got 2 camellias in my garden that has quite depleted soil overall, partially because of a massive pine tree that takes out all the nutrients and also I simply don’t know how to look after these camellias. One of them stopped blooming last year, was full of buds which never opened and fell off. While my neighbor’s camellia is blooming wildly. See the images .. please help me what can I do with them to save them and potentially have some blooms? Thank you