"cmake -DCMAKE_UNITY_BUILD=ON -B build" takes 11.1 seconds for me
"make -sj" in that build dir takes 2.3 seconds for me
but I normally use configure
A very "complete" configure run takes <10 seconds for me and then "make -sj"takes 3.4-3.5 seconds.
This is on a 13th Gen Intel i7-13700K running Linux.