Are you still using Windows 7 or 32 bit only?
You should update, because swtichting from 32 bit to 64 bit will speed-up generating a timetable ~10%.
Switching from Qt 5 (runs on Windows 7) to Qt 6 (doesn't run on Windows 7) increase around 8%.
So moving from Windows 7 32 bit to Windows 10 64 bit will increase the generating speed with FET around 18%!
(Also Windows 7 didn't get any security update anymore. There are security bugs in Windows 7 that won't be fixed anymore. It also look like you can still upgrade from Windows 7 to Windows 10 still for free.)
There are large speed improvements if you use latest Qt 6 Version and/or 64 bit.
I done speed comparisons for Windows:
https://youtu.be/nEmsf_-f6P4
and for Linux (Raspbian):
https://youtu.be/DejTeNM0T6I