FYI - HFS is capability of case sensitivity and is an option during formatting. I believe it even used to be the default.
The biggest problems I encountered were (1) occasional bugs with Homebrew formulas, and (2) Adobe's applications cannot be installed on a case-sensitive file system.
That was a problem with older versions of Adobe suite, but since lots of people on Macs used Adobe Apps...
So CS HFS+ is not glitchy, and CS APFS will not magically fix applications with CI dependency.