My reminders are not syncing from my phone to the cloud. I am running iOS 27.0.1 on a 16 Pro, which I updated to from iOS 27 while this issue was happening, but it failed to fix anything.
I turned off the reminders syncing and saved them all locally, and when I turned it back on all the reminders on the cloud downloaded to my phone, so now everything is duplicated, but adding new reminders to the iCloud lists on my phone still does not add them to the computer/cloud. It does seem like reminders being updated on my computer are adding to my phone, but not the other way around.