Many threads about problems with iCloud sync, especially if it involves non-Apple hardware.
iCloud is idiosyncratic and believes it knows best, even when it works. Some say they have it working. And, I suspect it usually does work some or most of the time even with PCs. But for sync, you usually need it to work all the time.
It’s worth checking the discord as well as the forum.
I use iCloud and switch between my iPhone, iPad & PC. Only once did PC kick up a fuss so far. It was not syncing but soon fixed by logging out of iCloud on PC and back in again. Not sure why this happened. Not happened since and when it did it was obvious it wasn’t working so not a big deal. Writing this on my iPhone and I would recommend it iCloud for free so far…
I use Obsidian (free plan) on a phone, a couple of iPads and my PC with iCloud as well as a couple of other apps (1Writer & beorg) on all devices. From time to time iCloud sync is slow on the PC but the other devices are fine and fast. Have used beorg on iCloud for about a year without any major issues. Probably 1Writer and Obsidian for about 6 months and again without major issues. The small problems I have encountered have been obvious and no worse than those encountered with OneDrive, Google Drive or Dropbox. Hope this helps.