1. It is known that a Titan would need to ingest a Titan shifter's spinal fluid in order to get their powers.
2. Zeke is able to extract his spinal fluid which he uses to turn other Eldians into Titans.
So if a Titan ingests Zeke's spinal fluid that he had extracted, would that Titan become the new Beast Titan and Zeke loses his powers? Or would Zeke retain his powers, creating the possibility for multiple Titan shifters?
Hey, who knows, maybe that's Zeke's plan! An army of Beast Titans would certainly be unstoppable ;)