Shiny odds for Shadow Beldum raids

I’ve been spamming shadow beldum raids in hopes of finding my dream shiny pokemon, but the more I try to research the shiny odds, the more confused I become.

I keep coming across conflicting information that may be out of date. I’ve heard 1/512, 1/256, 1/64, etc. but can’t find any definitive conclusion

This post from fleeceking (2 years ago) says shiny odds for shadow raids are 1/64, and this wiki page also says that pokemon encountered from raids are 1/64.

Does anybody actually know what the shiny odds are in this case?