To progress further with the initial flashlight idea, controlling the flash directly appears to work fine in the following way.

#!/usr/bin/env bash

flashOff() {
	printf '%s' "0" > /sys/class/leds/led:torch_0/brightness
	printf '%s' "0" > /sys/class/leds/led:switch_0/brightness
}

flashOn() { # 2 appears to be the minimum brightness value possible
	printf '%s' "2" > /sys/class/leds/led:torch_0/brightness
	printf '%s' "1" > /sys/class/leds/led:switch_0/brightness
}

So with a loop I can have a nice flashing pattern at the minimum brightness.
Just need to find what to hook into so I can have it only running only while there is a green notifications icon.

As for using the screen, I think the green envelope icon, possibly slowly moving along the top edge of the screen (to minimise any burn in); would be a nice option there.

@knuddel823 It's recommended to install Fairphone version of Android 13 as per the install instructions.
https://devices.ubuntu-touch.io/device/fp5/release/noble/#installerDownload

Run the installer, it should detect your device and then use the option to reinstall but don't tick the wipe personal data option.

Comparing with flashlight on and off.

Off
/sys/class/led/led:switch_0/brightness = 0
/sys/class/led/led:torch_0/brightness = 0
/sys/class/led/led:torch_3/brightness = 0

On
/sys/class/led/led:switch_0/brightness = 1
/sys/class/led/led:torch_0/brightness = 127
/sys/class/led/led:torch_3/brightness = 127

I'll need to test if changing these will trigger the light, certainly just making switch_0 = 1 doesn't work.
Not sure if this is the correct way to interface with these.

As for monitoring for new messages I'm wondering if dbus-monitor could be used...

It doesn't seem bricked from what you have said.
If bootloader is unlocked try the installer again, maybe from another machine or try another port or usb lead.

@knuddel823 It's recommended to install Fairphone version of Android 13 as per the install instructions.
https://devices.ubuntu-touch.io/device/fp5/release/noble/#installerDownload

Run the installer, it should detect your device and then use the option to reinstall but don't tick the wipe personal data option.

@RJDan Yes you need the Fairphone version as per the install instructions.
https://devices.ubuntu-touch.io/device/fp5/#installerDownload

@keb You can use the installer to reinstall without wiping personal data.
If that doesn't fix it you can try backup calls, messages and your personal files then full wipe.

I am not certain if this is the issue but I had similar issues with the Music app.
I found if you remove one of the core apps it leaves a broken symlink in /opt
When you remove that symlink and reboot you can get it from the openstore again.

@CatWithUT

I don't have the same findings as yourself.
I think it's at the point were I'm not sure how useful a long list of "working" things is.
There are things that seem to work but break or have regressions between the quick update cycles.

GPS is fine, it takes a very long time with the screen on to get your first fix. If you use the GPS from then daily (I've had the weather app set to detect location), GPS is relatively quick to fix.

Camera you occasionally get a black screen and have to flip between front and rear camera in the app.

I can't get any USB DAC to work to far. I'm using bluetooth headset for now.

Libertine will not install due to libc6 mentioned in another recent thread.

Convergence (Desktop) mode is very clunky to switch between and has slight issues but "works"

No issues with vibration what so ever, in fact I'm very happy with it.

I'm not sure works as a stopgap is fair. It's not perfect and I feel UT as a whole is lacking some QOL features but totally useable for a Devel branch device. I have no requirement for a backup device.
I'm hopeful Noble will iron most of the above out anyway.

To progress further with the initial flashlight idea, controlling the flash directly appears to work fine in the following way.

#!/usr/bin/env bash

flashOff() {
	printf '%s' "0" > /sys/class/leds/led:torch_0/brightness
	printf '%s' "0" > /sys/class/leds/led:switch_0/brightness
}

flashOn() { # 2 appears to be the minimum brightness value possible
	printf '%s' "2" > /sys/class/leds/led:torch_0/brightness
	printf '%s' "1" > /sys/class/leds/led:switch_0/brightness
}

So with a loop I can have a nice flashing pattern at the minimum brightness.
Just need to find what to hook into so I can have it only running only while there is a green notifications icon.

As for using the screen, I think the green envelope icon, possibly slowly moving along the top edge of the screen (to minimise any burn in); would be a nice option there.

This isn't a feature in Ubuntu Touch yet either is it?
Would there be any burn in concerns using the screen?
I certainly miss having a flicker of a notification led every few seconds for missed calls and messages.
I didn't expect to miss a small feature so much on this device.

Comparing with flashlight on and off.

Off
/sys/class/led/led:switch_0/brightness = 0
/sys/class/led/led:torch_0/brightness = 0
/sys/class/led/led:torch_3/brightness = 0

On
/sys/class/led/led:switch_0/brightness = 1
/sys/class/led/led:torch_0/brightness = 127
/sys/class/led/led:torch_3/brightness = 127

I'll need to test if changing these will trigger the light, certainly just making switch_0 = 1 doesn't work.
Not sure if this is the correct way to interface with these.

As for monitoring for new messages I'm wondering if dbus-monitor could be used...