Deletions from PC not synchronising with iCloud Photos

I recently installed iCloud for Windows on my Windows 11 PC. Once everything was synched, I had a sort out of my entire photo library, deleting hundreds of junk files. I did it this way because I found it easier to browse tons of photos with a large monitor. However, these deletions don't seem to have synchronised to iCloud. I can still see the deleted files on my iPhone and in iCloud Photos via a web browser. I have tested this out and one-way synchronisation does appear to be working, because new photos I take on my phone are appearing almost immediately on my PC. But if I delete the new photo on PC, I can still see it on my iPhone hours later.