I think you are a missing part of it. The FSB/KGB/NKVD was always the Fredo of Russian intelligence. If the GRU did, he’d be dead. and we’d never know about it.
Excellent point. During the Cold War, the GRU often proved to be a more formidable adversary than the KGB, and it presumably remains so today. After the FSB botched the job of subverting Ukraine’s leadership so as to make the Russian invasion a walkover, the GRU was put in charge. It is not clear if they are more effective though.