Regarding OneNote, I use it daily across several devices for work, personal, and extra-curricular endeavors (mostly nonprofit/volunteering kinds of things), and have done so for many years. I share OneNote notebooks with people in the same M365 tenant, people in other M365 tenants, with people who have MSAs. It’s fair to say I’m a OneNote power user and agree 100% with the frustration part. What bothers me more even than issues related to syncing and sharing notebooks (which can be insanely frustrating) is the neutering of OneNote in the non-Windows versions. I use OneNote Page Templates which, quite simply, just create a new note and paste some text into it. I do this so that when I’m meeting with a customer, I have spots to include relevant information and this keeps me from forgetting to ask or record something. Problem is, Page Templates only exist in OneNote 2016, and even for Notebooks stored in OneDrive, the Page Templates themselves are stored locally on the PC. Good grief.