Recently, 5G technologies has developed in some parts of the world, enabling them to achieve high-speed internet, uninterrupted mobile communication, and the internet of things (IoT). However, it was not sufficient for industrialization, automatic driving vehicles, vehicle-to-vehicle communication, and military artificial robotics. As a result, more cutting-edge technologies, such as Terahertz frequency band spectrum, Cell-free Massive MIMO, Laser, and VLC communication, CMOS-based Gas and InP antenna design for scalable transceivers, reconfigurable intelligent surface-based multi-antenna MIMO, underwater communication, machine learning, recurrent neural networks, and satellite broadband communication, are required to cater to those high throughputs and URLL that are possible through future 6G technologies. The future 6G technologies include critical speed, security vision, and artificial intelligence-based communications based on cutting-edge technology. 6G speeds are a thousand times faster than 5G, and latency is a hundred times lower. 6G is expected to enable augmented reality and virtual reality communication across underwater, satellite, and global backhaul cloud networks. Beyond 6G, promising technologies such as the internet of Nano things, the Internet of bio-Nano things, and quantum communications, which are expected to have a significant impact on wireless communications, are expected to emerge. Above all, this paper will present issues, solutions, and future directions of 6G and beyond.