Kubfu is going to be the main focus of a lot of teams moving forward, both in the competitive tests and casual play in the Pokémon Sword and Shield’s Isle of Armor expansion. But you’ll want to make sure you get your Kubfu and Urshifu trained properly the first time because it’ll be hard to redo their stats.
Since both Kubfu and Urshifu are Legendary Pokémon, you won’t be able to breed either part of the evolutionary line, even when using Ditto.
This means you won’t be able to have multiple copies of the Wushu Pokémon without trading with other trainers or restarting your own game to complete the Isle of Armor again.
You can use Pokémon Home to store your Urshifu and then restart to avoid purchasing another copy of Sword or Shield and the expansion pass, but that’s really your only option if you can’t find someone to trade you another Kubfu.
This doesn’t hurt the Pokémon’s competitive viability, but it does mean resetting it back to base stats and changing different aspects of its build to fit new playstyles will be much slower since you only have one version of the Pokémon to work with.
Almost all of Urshifu’s strengths will point you to maxing out its Attack and one other stat of your choosing, so building a competitively-viable version of either Rapid Strike or Single Strike Style will be easy enough.