I would suggest you try getting a paid subscription to Grammarly for a while and see if it helps you. I use it all the time and it catches no end of simply errors I could read a dozen times and never spot. Even the free version (which I use) might be a good start but I think the paid version does a lot more - you can probably find a free trial of the paid version too. Failing that try checking out Literotica.com and see if you can find a human editor on the forums there.