Yes, you can be a solo founder and operate a business alone. The sole proprietorship has, in fact, many benefits. Thus, it is usually cheaper to start a startup alone, no one tells you what to do, and you keep all the profits.
However, if you wonder how to build a startup solo, we’d say that a single person is incapable of handling everything necessary for disruptive growth.
For instance, you have to know how to start a startup from scratch, everything about your domain, keep a close eye on your competition, market your business, raise funding, manage a team of freelancers or outsourced specialists, etc.