I'm going through the same problem. I've used about 5 themes in a year but learning by myself html and css is extremely hard and after all this time I know it's mostly trial and error to fix things or just leave it alone. I take a couple weeks trying to find an answer and at the end of the day I end up mentally exhausted. I decided to take a learning course and get the basics of design. I can't afford to pay a designer $100 each time something messes up or wanna add a new thing...