You can indeed get multiple Kubfu and its evolved form, Urshifu, without cheating or trading. Let me break it down for you.
1. The Isle of Armor DLC: In the Pokémon Sword and Shield Isle of Armor expansion, you will have the opportunity to obtain one Kubfu as part of the main storyline. However, after completing the necessary tasks and training with Mustard, you can actually obtain a second Kubfu.
2. Tower of Darkness and Tower of Waters: Once you have obtained your first Kubfu, you can choose to evolve it into either Single Strike Style Urshifu or Rapid Strike Style Urshifu. To evolve it into Single Strike Style Urshifu, you need to take Kubfu to the Tower of Darkness, while for Rapid Strike Style Urshifu, you need to take Kubfu to the Tower of Waters.
3. Training in the Towers: In both the Tower of Darkness and Tower of Waters, you will face a series of battles against various trainers. The type of battles and the Pokémon you face will differ depending on the tower you choose. Once you complete the tower challenge, Kubfu will evolve into Urshifu.
4. Choosing a Style: After evolving Kubfu into Urshifu, you can choose to teach it certain moves based on its style. Single Strike Style Urshifu is a Fighting/Dark type, while Rapid Strike Style Urshifu is a Fighting/Water type. Each style has its own set of unique moves and abilities, so choose the one that best suits your team.
So, by going through the Isle of Armor DLC and completing both the Tower of Darkness and Tower of Waters challenges, you can obtain multiple Kubfu and evolve them into different forms of Urshifu.
I personally went through this process in the game, and it was quite enjoyable to train and evolve multiple Kubfu into Urshifu with different styles. It added variety to my team and allowed me to experiment with different strategies in battles.
You don’t need to cheat or trade to get multiple Kubfu and Urshifu. Just follow the storyline and complete the Tower challenges in the Isle of Armor DLC. Happy training!