SUMMARY
I'm not familiar with KDE Plasma specific terms so I'll just use the Windows equivalent terms to describe.
In the tray icon area there's the network icon, clicking it would open a fly-out that displays your active network connections, as well as available Wi-Fi access points nearby.

I find that when I leave my laptop running overnight without suspending, in the next morning everything related to Wi-Fi disappears from this network icon fly-out: The Wi-Fi toggle, my Wi-Fi connections as well as available Wi-Fi access points
. The icon turns to a disconnected Ethernet icon, and the fly-out still displays my virtual LXD bridge.

If I then go to System Settings -> Network -> Connections, my Wi-Fi access point shows as "Connected", and in fact I can still use Internet at this point.
I can use `killall plasmashell; kstart plasmashell` to restart plasmashell, and then the network icon and its fly-out will go back to normal and display Wi-Fi correctly.

This issue doesn't seem to happen if I suspend my laptop before going to sleep, it only happens if I leave it running the whole night.


STEPS TO REPRODUCE
1. Use a laptop, change power settings to never sleep
2. Lock the screen before going to sleep and leave it running overnight
3. In the next morning, unlock the laptop and check the network icon in tray area

OBSERVED RESULT
The network icon turns into a disconnected Ethernet icon, clicking it to open the fly-out and it seemed as if there were no Wi-Fi hardware on my device. However, in System Settings my Wi-Fi access point still shows as connected and I can use Internet normally.

EXPECTED RESULT
The network icon should still show my Wi-Fi connection and nearby access points, as well as the Wi-Fi toggle.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.10

ADDITIONAL INFORMATION
Kernel version: 6.5.4-1
Wayland session (though this should be unrelated).
Marvell Wi-Fi card.
`ip ad` in Konsole shows my IP address of the Wi-Fi connection correctly.
Only problematic part seems to be that tray icon and its fly-out.
I don't think I can reliably reproduce this issue, but it occurs.