Safari Reading List doesn't sync

I have a MBP M1 and an iPhone 11Pro. I am not sure when the issue began, but I noticed it today. The Safari bookmarks sync fine and instantly across the two devices, but the reading list is dead. If I add or delete a website to/from the list from either device it doesn't show in the other. So I am not even sure which device isn't syncing, or if just both aren't. I tried all the steps on the Apple support pages of removing Safari from iCloud and re-adding it on both devices but that didn't do anything...