Union the layer with itself as input layer, no overlay layer

Aggregate to drop duplicate geometries and keep the one with maximum year:

Then dissolve by year

Union the layer with itself as input layer, no overlay layer. Duplicate geometries will be created where the polygons overlap.

Aggregate to drop duplicate geometries and keep the one with maximum year:

Then dissolve by year

Union the layer with itself as input layer, no overlay layer

Aggregate:

Then dissolve by year

Union the layer with itself as input layer, no overlay layer

Aggregate to drop duplicate geometries and keep the one with maximum year:

Then dissolve by year