My experience of using HP Pavilion X360 15-cr0xxx serie and another compatible HP Active Pen 1MR94AA/Microsoft Universal Pen standard
I have HP Pavilion X360 15-cr0xxx series, updated to latest BIOS, drivers etc.. According to HP web site, the digitiser screen works with two HP Pens (using Microsoft Universal Pen standard) : 1MR94AA and 2MY21AA. So, I bought a compatitble OEM one for about US$22 from AliExpress, seemed to work straight away with the defaults Windows 10 Windows Ink, namely, one button to select and one button to erase.
However, I have installed the HP Pen Control sp80343.exe from your (a previous poster on this thread) link to FTP site today (because Windows App Store said my laptop was not compatible). This OEM pen seems to work fine. For example, I used this App and changed to top button to act as "Windows Start Key", and it worked, pressed button with pen nib touching the screen opened Windows Start.
(For others reading this, the HP Support Web site for HP Pavilion X360 15-cr0xxx series links to https://support.hp.com/gb-en/document/c05478395 (but when I went to Windows App Store, it said my HP Pavilion X360 15-cr0xxx was not compatible, so I could not install from Windows App Store! So, use the FTP site for the HP Pen Control sp80343.exe )
For convenience this HP Pen Control sp80343.exe works with:-
HP Spectre x360 Convertible
HP Pavilion x360 15 Convertible
HP ENVY x360 15 Convertible
HP ENVY x360 15m Convertible
HP Pavilion x360 11 Convertible
HP Pavilion x360 11m Convertible
HP Pavilion x360 14 Convertible
HP Pavilion x360 14m Convertible
HP ENVY 17m
HP Spectre x2