Hi all
here is a link to RAM, a very popular turbocharger company that specializes in aircraft turbo systems.
You can get any good quality penetrating oil to work for cleaning the shaft but the one they recommend is the aviation standard for Canada and USA. Rotax says you can use anti-seize however that should only be used after the shaft is clean and free from application from the penetrating oil.
Most Rotax turbos have a small port directly to the bearing surface of the wastegate shaft.
Note that in some states, California is one, you can not buy the aerosol cans of penetrating oil.
You can use a normal liquid version and a simple squirt can.
https://www.ramaircraft.com/turbowastegates#:~:text=RAM%20strongly%20recommends%20that%20the,a%20common%20oil%20squirt%2Dcan.
All this is explained in the Rotax Service Information
Cheers