Keynote/Pages does not display some fonts

When you download the Heebo font from Google, it will download a compressed Zip file containing a single variable font (e.g. Heebo-variablefont_wght.ttf, and a folder named static containing a larger collection of Heebo fonts. The variable font contains seven Heebo typefaces and the static fonts are nine. In either case, I created a new folder named Heebo in my /Users/viking/Library/Fonts folder and initially placed the variable font in it alone.

What I found in practice is that at minimum, one must logout and back in to macOS in order for Pages to see the Heebo font, whether the single variable font-face font, or the separate nine static faces, depending on what you copy into that Heebo folder.

Pages 13 on macOS Ventura 13.3.1 using the nine Heebo static fonts:

These nine faces validated correctly in Font Book.

I didn't bother to reboot, but just to logout. Whether I dragged the Heebo-VariableFont_wght.ttf file into the /Users/viking/Library/Fonts/Heebo folder, or replaced it with the nine static fonts, upon signing back into macOS Ventura, Pages was able to see the fonts in its font viewer (as I displayed above). The fonts must have the .ttf extension on them.

As you observed, years ago when I downloaded the Roboto font from Google, it just worked without needing to cycle logout. It may also predate Google providing variable (*wght.ttf) fonts.

Does it appear on the list in Pages > Format > Font > Show Fonts > All Fonts?

You might try getting a copy of that font from another source

Do you have this problem with any other font from Google?

PS Heebo from Google works fine in Pages on my Monterey system. Will try to test with Ventura sometime later.