Well. That's fun! I wonder if by January 2026, maybe they will somehow make the results more predictable and we won't lose data.
Hold on... it's coming up. But also, it's going away.
Oh ok, they updated the Data Center 10.0 (Latest) docs for the Navigation Map macro with this infobox:
Want more flexibility? Check out the Content by Label Macro for a more modern way to display a list of pages with specific labels and more.
Huh, more flexibility you say? Ok, well, a Navigation Map looks like this:

It's configured with Labels. Oh I see, just like Content by Label Macro is configured by... right, Label. So there's probably a way to use that Macro to produce a similar display, cool. Let's see...

Wait what? That doesn't look REMOTELY similar.
Surely there must be a "button view" or something right?
Nope.
But wait, it's still there? In the Cloud Editor?
Well, I guess the good news for my users is that Atlassian saw fit to convert Navigation Map as kinda-sorta supported in the Cloud Editor. So if you convert a Legacy Page that contains a Navigation Map, you can still configure it in Cloud Editor:

And it even turns out that if you REMOVE the px for Cell Height or Width the buttons actually change size. (Leaving px guarantees they will not change, so maybe "optional" is the wrong word.)
No New Navigation Maps
So let's say that you're just encountering Navigation Maps for the very first time and you're like, huh. That actually looks useful!
WELP.
Despite it looking like a real Cloud Editor macro (note the lack of the word "Legacy"), you cannot Insert a new Navigation Map macro:

Keep a Navigation Map handy on a page SOMEWHERE
If you think you may want to use this Macro (hey, maybe you LIKE its early 2000s aesthetic) you'd better insert it on a Legacy Page and keep around. Because after January 2026, there'll be no way to get one onto your Confluence site.
(OH, I guess maybe I should create a "Legacy Macro Space" full of pages that contain old Macros, and I could offer to copy it to people's Confluence sites upon request. Woof.)
Is there an Alternative?
I guess the other question is:
Does anybody know of an alternative to Navigation Maps that won't cost me an arm and a leg?
Ok, welp, thanks for coming to my TED Talk.