I think all of them are important but clearly Konrad Zuse has received way less attention than he deserves. Growing up I remember being taught that ENIAC was the first computer and didn’t even hear about the Z1 to Z4.

But reading up on the details I find that utterly unfair. ENIAC e as way too far away from a programmable machine. It was computation units which just got wired together in different fashion. That is very removed from what a computer is today. The Z1 and later is far closer to what we think of as a computer IMHO, with actual programs being fed into it decoded using registers and and ALU etc.