many office packages are notorious and load loads of
default-sheets in advance plus fonts that might be never used.

together with the anyway extensive simultaneous
program-starts when the computer boots up a torture
for the poor multitasking-qualities of windows (switchtimes about 100-1000 times longer than MacOS)

a nice trick for those who regulary work with a lot of
office-applications in one session is to start
those programs via the commonly neglected taskplaner that
offers a 'time-after-bootup schedule' as option ...

a basic option are programs like 'startstop' (freeware)
scanning registry/INIs for custom/hidden program calls
and offering a list during windows-start for a possible intervention.