emacs font scaling does not work

Ubuntu 22.04.2 LTS with all updates.
Emacs 1:27.1+1-3ubuntu5
Default (Wayland) windows.
Lenovo ThinkPad X1 Yoga Gen 7 with 4k display.

Monitor setup:

Internal 4k display, external FHD display adjacent in workspace.

Expected:

Emacs should scale fonts when moving from one monitor to another, so it looks pretty much the same, despite the big difference in DPI (over a factor of 2 in reality, though this is not indicated in the output of xdpyinfo).

Actual:

Dragging the window to an external FHD monitor makes the window size stay about the same in cm and the font inside it really large, leaving well under 40 characters of width and just a couple dozen lines, if that. It's unusable.

Suggested solution:

Emacs 27 does not support font scaling under Wayland. I do not know if it does under X11.

Emacs 29 has a configure option, --with-pgtk, that fixes this for Wayland displays. I tested it in Emacs 30. Emacs 29.1, the next stable release, will come out in a few weeks. I do not know if this solution works on both X11 and Wayland in the same binary. I'm not an emacs dev, but they may know.

Please make Emacs 29 available as soon as it comes out, with font scaling enabled for both X11 and Wayland if possible, and certainly Wayland, the default window system.

Thanks,

--jh--

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: emacs 1:27.1+1-3ubuntu5
ProcVersionSignature: Ubuntu 5.19.0-38.39~22.04.1-generic 5.19.17
Uname: Linux 5.19.0-38-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu82.4
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Wed Apr 26 12:58:17 2023
InstallationDate: Installed on 2023-03-18 (38 days ago)
InstallationMedia: Ubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64 (20230223)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: emacs
UpgradeStatus: No upgrade log present (probably fresh install)