(Thinking really out of the box here���) IFF you���re really into getting this baby running, you could have a look at the following post. A dude is writing a Rust compiler for the PowerPC in order to run Firefox. Once you have Firefox, you could run SqueakJS with a Pharo image (from very old to more recent). If you���re okay with doing lower level stuff yourself, you could see if a PowerPC implementation of CogVM is possible, but I think it will be even more challenging. ;-)

https://dev.to/scottcjn/i-built-a-rust-compiler-for-a-20-year-old-mac-borrow-checker-and-all-37n7

Source code of the Rust compiler:
https://github.com/Scottcjn/rust-ppc-tiger