Well let's examine all the reasons you might suspect the silly Biden laptop story to have been planted by the GRU.
1: Rudy Giuliani is involved
2: Rudy Giuliani specifically traveled to Ukraine in 2019 to dig up dirt on Biden, a mission that he publicly announced.
3: Rudy Giuliani is the GRU's "useful idiot" according to a report prepared for the White House by US intelligence services.