Lack of tooling or documentation on how to optimize build of 3000 F# projects, where cpu is not saturated

Creating this issue as i was not able to find answer or get response on StackOverflow.
Im building 3000 F# projects in our CI, from scratch, on TeamCity. Perflog tab shows that during 2 hours it lasts, cpu is saturated only half of the time. This happens with VS2017 on windows server.
Im not after optimizing cpu usage, but rather understanding what msbuild agents are waiting for and if i could optimize dependency chain or smth else.
I tried enabling binlog, but msbuild hangs then and i cant access Build agents.
I tried sorting projects by number of dependants, so we build core project first (i have not tried -graph option yet)
F# is compiling files sequentially so may be more sensitive to thus problem than c# or cpp.
Have i missed docs or tools that would allow to optimize my build?
Expected: report and hints on what is causing delays in build.