Design has always been painfully slow for me as well, despite the ease with which I can implement a design handed to me. If you actually do want to get good at

Design has always been painfully slow for me as well, despite the ease with which I can implement a design handed to me. If you actually do want to get good at design I recommend just building five or ten nonfunctional web designs based on already built sites on the web. I bet you'd get better at laying out a decent site without bootstrap or anything else relatively quickly.