Also, it doesn't look like OpenBSD has binary packages for 32 bit PowerPC:
https://cdn.openbsd.org/pub/OpenBSD/7.7/packages/
Although I do see packages for OpenBSD 7.6 from last year:
https://cdn.openbsd.org/pub/OpenBSD/7.6/packages/powerpc/
There's always NetBSD, though, which has tons of binary packages and which isn't going to be dropping architectures like PowerPC any time soon :)