If you’re talking about the assassin that was just sent back, he wasn’t from the team who had tried to kill Navalny. Wasn’t even from the same Russian intelligence agency, and those guys – especially after being identified – are, I imagine, never going to be leaving Russia again. Those guys were GRU. This guy was FSB.
The guy who just got sent back shot a guy in the head in a park in Germany. And while he still managed to get himself caught, he actually killed his target, and unlike the GRU guys who tried to hit Navalny, managed to refrain from performing a recorded confession to his victim, and unlike the GRU guys at Salisbury, managed to avoid killing random civilians and hurting a police officer and starting an international incident over Russia running an illicit chemical weapons program in violation of treaty obligations. Frankly, if I were Putin and set on having someone assassinated, I think I’d lean towards having the FSB assassinate people and focus on keeping the GRU well away from assassinations and preferably any sharp objects or heavy machinery.