CSD19534Q5A: Zero supply of CSD19534Q5A, footprint compatible alternatives?

I understand your struggle. All four of our 100V SON5x6 devices will be footprint compatible:

www.ti.com/.../n-channel-mosfet-transistor-products.page

The only catch is the CSD19532Q5B is a slightly different package (still footprint compatible), but we generally recommend the Q5B recommended PCB footprint if you are going to use both Q5A and Q5B as the more universal footprint because it is a bit larger.