A lot of materials will last 100s of years.
Remolded E-waste will not be that long lasting because it will be a mixture of different materials with different properties, some prone to weathering, some to hydroscopic effects, fatigue, brittleness etc. So you will likely have to develop a composite to be able to somewhat control mechanical properties.
Having said that, why not focus on less sustainable solutions that, when their lifespan is complete, can simply be remolded again and again, contributing to a circular economy adapting to the needs of the moment. Check out for example the work Oscar Andres Mendez Gerardino did with Unilever: https://www.unilever.com/sustainable-li ... Gerardino/
I also see great opportunities for composites from bio-waste - corn plants, palm leaves, beets, grasses etc.