Microelectronic assemblies, related devices and methods, are disclosed herein. In some embodiments, a microelectronic assembly may include a first die, having a first surface and an opposing second surface, in a first layer; a redistribution layer (RDL) on the first layer, wherein the RDL includes conductive vias having a greater width towards a first surface of the RDL and a smaller width towards an opposing second surface of the RDL; wherein the first surface of the RDL is electrically coupled to the second surface of the first die by first solder interconnects having a first solder; and a second die in a second layer on the RDL, wherein the second die is electrically coupled to the RDL by second solder interconnects having a second solder, wherein the second solder is different than the first solder.