Older ocean crust does indeed generally subduct at a steeper angle! Relatedly, if you have ocean crust that is relatively young and hot enough but is still colliding with continental crust, then you can get "flat-slab" subduction [1]
Once the crust gets deeper in the mantle, eventually metamorphic phase transitions become the most important factor. In some seismic images, it looks like subducted slabs make it all the way to the core-mantle boundary (where they may contribute to the source of new mantle plumes).
For sure, I would love to have that simulation!