I ran into the same issue, which seems to be related to the Anchor IDL build step. Using anchor-cli 0.30.1 solved the issue for me.

Thank you. Any hint for what's causing the "exceeded max offset of 4096 by x bytes, please minimize large stack variables" kind of issues? Seems Anchor specific, although apecs wouldn't work anyway for the async libs and missing syscalls as you mentioned. I'm hitting this issue with several existing libs.