Ah, then I suppose you'd be aware of my own forays into 64-bit ELFs (
https://tmpout.sh/3/22.html)! I really should get around to publishing my writeup of the 73-byte minimum on Linux. (At least, it's 73 bytes for x86-64, since '\177E' at the start of the file jumps to byte 71, but it may be different under AArch64.) I have a nearly-complete draft, but I got caught on some oddities around the vDSO mapping which may or may not have changed across kernel versions, especially since the time I wrote it. Perhaps I should just jettison that section entirely and get the article out, since it's not like any of the x86 vDSOs have useful gadgets anyway.
