How do I get a Notes Master in Powerpoint to actually apply to the notes?

I see that this question has been asked dozens of times by lots of people since 2010, and nobody has come up with a solution in the last 11 years other than writing some bespoke VBA, so I'm wondering if the "View | Notes Master" functionality is simply pointless as if it hasn't been fixed yet? However, I thought I'd ask anyway just in case there is a way of doing something that should be blindingly obvious.

All I want to do is put a footer on my notes pages in a Powerpoint (Office 365) presentation. I went to View | Notes Master, edited it so that it had a footer with my name in it and then closed the view. It had no effect on the notes pages at all. I clicked on a slide and chose "Notes Layout" and then ticked "Reapply Master" and OK, and that had no effect at all.

So my question is painfully simple but I can't find an answer to it - how do I get my Notes Master to apply to my actual notes? And if it isn't possible, what does the "Notes Master" actually do, if it can't be applied to a presentation?

Thanks in advance!

Chris.