My question is why whatever Calabria reported about McNuchin relevant? Calabria was a Mike Pence guy who now is irrevelant in GOP politics and McNuchin has not come out in support of DJT in past years to my recollection.
You are right that Mnuchin and Calabria are now history and no longer relevant. However, their - now "historical" - statements (published in Calabria's book) do tell us how Treasury and the FHFA Director internally thought about releasing the GSEs at the time, and what their expectations and demands were.
From Biden, Yellen, and Sandra T. we hear nothing but silence. That makes Calabria's relatively frank statements interesting even today.
One can assume that the general approach has not changed much since then. However, each administration has its own interests. Biden would probably prefer to continue the status quo indefinitely, using the GSEs as a piggy bank for stimulus and social programs that he could not otherwise get through Congress (the Democrats' "Obamacare" cross-funding tradition lives on here).
IMHO, the statements of Mnuchin and Calabria are mainly interesting to deduce what to expect in the next Republican administration (with POTUS Trump?) in terms of activities and conditions regarding a release. Although, of course, the Republicans may also have changed their premises. I wonder, for example, if Trump would stick to what he wrote in his famous letter.