Just playing a radio stream cranks up the CPU like crazy (plasmashell)

I listen to a lot of online radio.
Running Kubuntu (22 LTS) with a Ryzen 5600G.

Got about 10 docker containers running, CPU at 1.5%.

I got to my favourite radio’s website and play the live stream, CPU jumps to 28%!!!

Couldn’t believe my eyes.
Stopped the stream and tried to play with cvlc from cli: same results.
BTW the process taking all the CPU is plasmashell.
Even tried running in a Virtualbox VM, both from browser and from cli: same thing.
If I switch off the audio for the VM, CPU goes back down to 2% (stream still playing in VM but obviously no audio).

Installed Xcfe on my system, typing from there now, stream playing from cli, CPU: 3%.
Tried in Xcfe both in VLC and browser with same results, CPU wavered around 3%.

And BTW in Plasma of course CPU temp shot up and was hovering around 45C.
Now in xfce: 33C stream still playing.

Also I did not reboot, just logged off from plasma and loged on xfce.
So all the plasma stuff is still running (quite a few plasma-monitor processes).

Not by any means an expert, but seems to me something is seriously not right there.

So you use a web browser to play your radio stream?

I had some problems with Chromium-based browsers occasionally: they used a lot of CPU - normally updating them when a new version came out fixed their CPU-spiking in Plasma.
Or try an alternative like Firefox in the meantime…
But it was always the Chromium-based web browser causing the spike, not Plasma itself - so perhaps this was a different problem…

As for Plasma : there is a very good add-on for radio streaming that is called Advanced Radio Player - so you would not have to use a web browser anymore (it uses < 2-3% of CPU on one of my older machines).
You can find it here: https://store.kde.org/p/1313987
Possibly you will have to additionally install the package qml-module-org-kde-notification .