After the third attempt with different glues and fiberglass, I gave up on repairing a window crank for my RV. The original crank is made of a kind of foamed plastic which could not be plastic welded either.
My solution works flawlessly and the copilot has accepted my design.
No need to write that it is made in LightBurn , the material is 4mm acrylic. From start to finish, 2 hours were spent, the most “complicated” part was making the inner toothed ring, which has 18 teeth, 0.85mm high.
If anyone can use the lbrn2 file, I will post it here.