Manual from wiki is not working without sudo su. But you can add sudo su and this manual will work then.
Here is logs:
user@host:~$ sudo su
root@host:/home/user# flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
root@host:/home/user# flatpak install flathub org.getmonero.Monero
Looking for matches…
Required runtime for org.getmonero.Monero/x86_64/stable (runtime/org.kde.Platform/x86_64/5.15-22.08) found in remote flathub
Do you want to install it? [Y/n]: yorg.getmonero.Monero permissions:
ipc network wayland x11 devices file access [1] dbus access [2][1] xdg-config/kdeglobals:ro, ~/Monero:create [2] com.canonical.AppMenu.Registrar, org.kde.KGlobalSettings, org.kde.kconfig.notify ID Branch Op Remote Download
- [✓] org.freedesktop.Platform.GL.default 22.08 i flathub 142.0 MB / 142.3 MB
- [✓] org.freedesktop.Platform.GL.default 22.08-extra i flathub 9.5 MB / 142.3 MB
- [✓] org.freedesktop.Platform.openh264 2.2.0 i flathub 883.7 kB / 944.3 kB
- [✓] org.getmonero.Monero.Locale stable i flathub 61.4 kB / 54.4 kB
- [✓] org.kde.KStyle.Adwaita 5.15-22.08 i flathub 6.6 MB / 6.6 MB
- [✓] org.kde.Platform.Locale 5.15-22.08 i flathub 228.4 MB / 354.8 MB
- [✓] org.kde.Platform 5.15-22.08 i flathub 370.6 MB / 323.7 MB
- [✓] org.getmonero.Monero stable i flathub 55.9 MB / 56.5 MB
Warning: Not exporting file org.getmonero.Monero.appdata.xml of unsupported type.
Installation complete.
root@host:/home/user# flatpak run org.getmonero.Monero
2023-04-29 00:35:58.218 W Qt:5.15.8 GUI:- | screen: 1916x938 - available: QSize(1916, 907) - dpi: 96.0347 - ratio:0.750228
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.240 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.261 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.261 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.270 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.270 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.270 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.270 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.271 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.271 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.271 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.271 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.290 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.290 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.506 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.514 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00:36:00.642 W Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
2023-04-29 00: