@peter33699, Sometimes, those kind of rotary switches can be saved by spraying it with electronic cleaner spray, at least enough to have it last until you can find a suitable replacement switch.
Unplug the device from power and either let it sit for a while or “power it on” to discharge residual charge inside.
Get some electronic cleaner spray (preferably deoxidising), CRC makes a good one that I use. Then spray “inside” the rotary switch, and spin it several times in order to work the cleaner inside and cleaning the points. Spray once more and repeat the spinning. Let it dry off for an hour or so, the cleaner evaporates quite quickly.
Plug it back in and test the switch / selection. Hopefully this will help until you get a decent replacement. I’d help with parts info if I could, but those kind of ovens are very rarely seen in Norway, and I’ve never seen that manufacturer.