The issues with finding builds for Microsoft Windows platforms was what got me into GIMP development. Not for the releases, because those usually came about in a matter of days, but daily builds (or sometimes hourly) which tracked development exactly.
But make sure that they don't make sliders too small - you'll lose the ability to do either fine relative or coarse absolute adjustments by dragging their lower or upper half.
Yeah, you most likely got rid of an existing cache, which couldn't be updated due to file locking. That issue is fixed in recent versions of the fontconfig library.
A fairly current one is shipped with the 2.9.6 installer, so many of the infamous issues should be gone.
The fontconfig cache is created on all platforms - it's just that this step is usually done when installing the system or adding new fonts from the package manager for your average Linux distro. Granted, it also works much faster there in general.
Adding a few new fonts for a specific project does not cause long delays on any platform.
A compounding issue was that file locking issues prevented successful cache updates on the Windows platforms until recent versions of fontconfig, this lead to a long startup time on every start.
Help > Search and Run a Command /
/ is also a common shortcut to invoke a quick find text entry, for example in web browsers.