I use iPhoneXR/iOS13 and MBP/Catalina. It takes minutes (not seconds as it used to) for a Mac note to appear in web icloud. But the worst is that it takes hours before the note may appear on the iPhone. And reverse is true – notes from iPhone don't sync to web and Mac. Also there is one folder I keep deleting(tried on all devices multiple times) and it keeps reappearing.
I have tried to sign out and back in with icloud, on both devices – no success. Actually the opposite – I have lost some notes which were not synced yet. I have also: iPad Pro iPadOS13, where notes are turned off to sync, iPad mini with iOS10 where notes are turned off.