It depends on her personality. That could make the difference between choosing completely opposite approaches.

Example: if she has some narcissistic traits and is very defensive when disagreed with, I would recommend redirection. Rather than point out what is wrong with what she is saying, you can change her focus to be on better ideas and thoughts. Then give her time to digest, as defensive people might be dismissive at first but then come back two days later to tell you about how great the thing you recommended was.

On the other hand, if she responds well to disagreement and prefers to receive direct feedback, prepare and practice a few talking points. In my experience, the best way to approach with a direct criticism is to use the "I feel" perspective as much as possible. Here is an example: "I agree that the ultra-rich business owners are responsible for so much evil in the world, but when you focus so much on Soros and use X references it sounds like the same things said by antisemites, and I would be sad if my mom thought those things. Would it be okay to talk about the things that other billionaires do and the antisemitic tropes used to focus on Soros alone?"

Obviously there is no guarantee of success, this depends mostly in your mother and not how perfectly you approach the issue.

Finally, it is also okay to just survive for a few months and avoid the topic. You don't have to take risks when you are precarious just to correct this grown woman that is embracing hate using a poor understanding. And you can disagree with her after you are no longer precarious. So that is just as valid of an option.