Creating Portfolio Projects as a Full Stack Developer

I'm pursuing a career in Full Stack Web Development, and have the ability to create web application's front-end and create API's etc in the back-end.

I'm now looking to create portfolio projects which can demonstrate my work to future employers. I want them to look good and professional, however, I am not a web designer, meaning I cannot create good-looking designs using tools like Figma, Sketch etc. Sure, I can create them if someone passes me the design using front-end tools such as HTML, CSS, JS and React.

How would I go about creating portfolio projects that look professional without being a designer. I'm aware of sites such as Dribbble that allow you to view other designer works. Although they usually only show a single picture view of the design without providing the files in which I can see the spacing / exact colours and typography used as well as the additional pages.

Perhaps you could link Websites, or services where I could get designers for cheap, or free as they are only going to be used for portfolio projects (non-commercial). I've tried messaging some designers on Dribbble if I could use their designs they usually allow me to use their designs however never send the design files and pages, so I'm stuck with a png file of just one view of the application.

I'm looking forward to creating a full-stack web developer portfolio consisting of web applications rather then static web pages, however having trouble finding designs.