Got PC and Laptop here (High-end, Z390 platform) both with modified BIOS to expose HPET option (Verified and works).
On 1809 LTSC there is zero evidence that either enabling or disabling does anything what so ever, let alone for gaming.
(Not in the DPC/ISR latency, timer performance, frametimes, etc)
The only thing that affects everything is having HPET enabled in BIOS and then force this platform timer as the default (With useplatformclock yes).
Even windows itself will start becoming slow as hell, that is because there is a bug with the later Intel systems that makes accessing HPET timer incredibly slow.
Some people have said in the past that 'disabling HPET' will significantly improve things, this is mostly caused by software that FORCED HPET as the global system timer to begin with. (AMD software that literally adds bcdedit entry, etc) which is NOT the default from Windows 10. There should not be such an entry in BCD at all. (Imagine some random software just doing this on an Intel system and the user was never aware of it)
Even if Windows does NOT use HPET by default as the system timer, it is still recommended to keep it enabled in the BIOS, as per Microsoft;
"To reduce the adverse effects of this frequency offset error, recent versions of Windows, particularly Windows 8, use multiple hardware timers to detect the frequency offset and compensate for it to the extent possible. This calibration process is performed when Windows is started."
Lastly, I want to say that different timers (Also Windows timer resolution) can have very subtle effects, in regard to gaming it can for instance increase the granularity and accuracy of the in-game frame limiter, which is beneficial for tearing and especially G-sync)