Degree to which Outlook Online supports search phrase syntax

Question

I'm very clumsy at using GUIs, so I try to avoid the Outlook Advanced Search GUI. I recently found the following salvations:

• https://support.microsoft.com/en-us/office/learn-to-narrow-your-search-criteria-for-better-searches-in-outlook-d824d1e9-a255-4c8a-8553-276fb895a8da
• https://www.howto-outlook.com/howto/searchcommands.htm

Unfortunately, it doesn't seem to work with "Outlook Online". I hope used the right term. It is web access to Outlook on Office 365, which I thought was called OWA, but now I suspect it is Outlook Online.

Anyway, I have a message in folder InboxNot containing the word "Mandatory". It is not found, however, with the following search phrase:

Mandatory folderpath:InboxNot

Is there an authoritative document on the search syntax for Outlook Online versus Outlook desktop application?

Afternote: I found this from the OWA help facility:

• https://support.office.com/en-ca/f1/topic/search-mail-and-people-in-outlook-on-the-web-b27e5eb7-3255-4c61-bf16-1c6a16bc2e6b?NS=OLWAO365B&Version=16

Scarily, it seems very limiting. I hope it is not the full story. Hoping that there is more to this....