I would highly recommend Grammarly for proofreading. It does a great job of catching a lot of grammar mistakes that other programs miss. You will need to be able to train it to recognise your specific writing style, but once you do it will do a better job than any human proofreader. Grammarly's ability to detect and correct grammar errors and usage issues across multiple documents is really quite impressive. I am currently using it to check over articles before submitting them to various platforms. As a copywriter and writer, it has been a godsend.