I have been reading on The Document Foundation blog about the ODF and how Microsoft basically gaslighted us all into believing the OOXML is truly an open standard when it actually doesn't even use the ISO's standardised version of strict OOXML as a default in his office suit, which obviously makes ODF the better choice; but I am not knowledgeable about the PDF.

From what I've found, it was developed by Adobe up until 2008; since then, it is an "open standard" supposedly developed by the ISO.

Does this mean the Portable Document Format is legit the way ODF is? If not what would be the open alternative to PDF that ODF is to Microslop's?

DOCX is supposedly an open standard too, the thing is neither Microsoft nor Adobe fully follow it and instead opt to make it slightly incompatible in order to make it hard for competitors to use it without issues.

EEE tactics.

The PDF standard is so complex that it makes it implicitly not really open, as it's basically impossible to implement it fully

Pretty sure odf extension is what LibreOffice uses for a "Word" doc, so I would hope it's open. Now whether or not MS properly uses it is another thing entirely.

My very cursory understanding is that there is a subset of PDF that is open, something called PDF-A I think, at least enough that it's used for archival. Source: my fingers, fingling on the keyboard.

DjVu probably but it's old and nobody uses it. PDF isn't ideal seems to be workable enough, it was always a much more functional way to share documents than doc or docx.

fingling

docx is OOXML, Open Office XML.

However, it was definitely written to ensure existing doc files could be fully supported, so a lot of the format is "bit 7: if enabled, use Word for Mac 5.0 layout engine." So... Documented, yes. Usable, no.

PDF, as mentioned, is very similar. The format is available, but no one really wants to implement ALL of it.

You want https://en.wikipedia.org/wiki/PDF/A