I, for one, noticed that when installing 6.2.4, changes had to be accepted and some items were deleted, which could have caused a problem.
The small difference with your distribution is that I can't even see the device in the Dolphin pane.
I'll be patient and wait for a possible change for the kde plasma 6.2.5 version available at the beginning of 2025.
Happy holidays!

When I plug the phone in is starts charging (in the appropriate mode according to its on/off state at the time).
But if plugged in while the device is on, it does not appear in the USB devices menu in the KDE toolbar.

It does however appear to be recognized by the OS as the dmesg output is sensible:

[489387.766340] usb 2-1.3: new high-speed USB device number 10 using ehci-pci
[489387.865961] usb 2-1.3: New USB device found, idVendor=1209, idProduct=0002, bcdDevice= 4.04
[489387.865971] usb 2-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[489387.865974] usb 2-1.3: Product: 5T
[489387.865976] usb 2-1.3: Manufacturer: OnePlus
[489387.865978] usb 2-1.3: SerialNumber: d7dfe97c

and it shows up in the list of USB devices in the system info tool. It also appears in the dolphin "Places" sidebar, but when I try to access it via that, I get an error:

Could not access device. Make sure it is unlocked, and tap "Allow" on the popup on its screen. If that does not work, make sure MTP is enabled in its USB connection settings.

I do not see (and never have seen) an allow popup on the screen, but according to the UT tweaks tool MTP is enabled (and it does not allow me to disable it).

FWIW, on the PC:

$ pacman -Qs android
local/android-tools 35.0.2-7
    Android platform tools
local/android-udev 20241109-1
    Udev rules to connect Android devices to your linux box
local/gvfs-mtp 1.56.1-1 (gnome)
    Virtual filesystem implementation for GIO - MTP backend (Android, media
    player)

(Omitting a few libcamera related matches)

the various options you suggest, dear helpers, will be tested, starting with a openSuse Slowroll image version 2024-11-17.
I'll need some time to come back and talk about it.
Thank you

This is an option I'm considering after those explained above ....
So I need a little time to try out these options and I'll get back to you as soon as I can.

The OP5T doesn't get the dialogue asking permission for "USB debugging". Devices shows as charging. This is a known working USB port and cable.

EDIT:

Solved my issue on Windows by elevating the command with ./ in front of the adb devices, i.e.:

./ adb devices

ADB picked up my OP5T fine and can tell it to reboot bootloader.

@vince-vs Try with an elevated command i.e. use sudo in front of adb. Sudo is not usually installed by default on opensuse from my memory so you may have to install it.

@vince.vs. Could you boot up a live version of Ubuntu and see if your device is recognized in that? If so, then you know it has nothing to do with the OTA, but with an update on OpenSuse.

https://forums.ubports.com/topic/10627/focal-ota-7-available-today/5?_=1733418376741