I'm not seeing where that article indicates that Biden or Merrick has pressured anyone to go outside of their reasonable investigatory powers regarding Rudy. I do see where Rudy's dealings have been an issue for over a year ( by the way Biden wasn't in office then).
"Federal prosecutors have been looking at Giuliani for nearly 1-1/2 years.
In November 2019, they sought records of payments to Giuliani as part of an active criminal investigation, according to a grand jury subpoena seen by Reuters."