Created attachment 138725 [details]
Here is the applet's configuration

SUMMARY
When creating/editing a connection with manual speed settings within the plasma-nm applet, it is not possible to choose a value of 2500/5000 Mb/s.

STEPS TO REPRODUCE
1. Open the plasma-nm applet
2. Create a new connection
3. Attempt to change the speed

OBSERVED RESULT
2500 Mb/s and 5000 Mb/s are not available

EXPECTED RESULT
Either 2500 Mb/s and 5000 Mb/s should be available in the Speed dropdown, or entering a manual value should be allowed.

SOFTWARE/OS VERSIONS
Linux: 5.12.6
KDE Plasma Version: 5.21.5
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Manually editing the connection with nmcli sets the speed as expected, however the value displayed in the applet's editor/viewer shows 100 Mb/s.

Here is the nmcli output:
```
$ nmcli connection show Onboard | grep 802-3-ethernet.speed
802-3-ethernet.speed:                   2500
```