On Sat, Nov 06, 2021 at 04:55:45PM +0100, fatiparty--- via Users list for the GNU Emacs text editor wrote:
> 
> Nov 6, 2021, 15:40 by daniel.herzig@outlook.at:
> 
> >
> > Increasing and decreasing font size works for me (emacs 27.x.y [at least since 26] on pure Debian, Raspbian,  Guix, and  Windows 10)   using the built-in keybindings ‚ ~C-x C-+~, and ~C-x C--~, respectively.  I haven’t had a look though which functions are called by these bindings.
> >
> >
> 
> I am using GNU Emacs 27.2.  I get text-scale-decrease and text-scale-increase to work correctly 
> after using "emacs -q" on the command line.

So something in your init files is messing that up.

Another font, perhaps? One that "resists" scaling?

You could slice up your init files and try a binary
search.

Cheers
 - t