Absolutely not! While it’s incredibly helpful to be proficient in C++, knowing just a bit can open up massive possibilities. Being proficient would however make the build process a bit easier, it’d make creating data oriented systems better, and allow you to build the engine from it’s source and change the engine itself when you need to!
Blueprints can take a game from concept to minimum viable product easily, and simpler games can actually be created in just blueprints! However I would highly recommend learning at least the basics of C++ and how it’s used in UE as it will make your development life far easier in the future. The learning path includes a small intro, but I would highly recommend a bit of a deeper dive especially if you plan to work in the industry at large as a developer or plan more complex systems for you game.