I doubt this is an issue. Google may or may not be able to detect AI content, ultimately, what they do about it depends on whether the content in question is used in a context that helps or hurts Google's business model.
If the content is garbage, in a site full of other garbage that ends up having a really high bounce rate, and users don't use the site properly and don't move from page to page in a manner suggesting they find the content useful and/or relevant, then the site isn't really Ads-worthy in a sense, so Google has a lot of incentive to find sites like these and weed them out.
If on the other hand, the content is machine generated, but is useful enough that there's a lot of traffic that stays on the site and uses it, then the fact that it's machine generated doesn't really take away from its utility. In such a case, I doubt that Google is incentivized to penalize that site.
There's definitely a grey area here, there may be many false positives, but if you design your site for user engagement, you shouldn't have too many problems, even if the content is AI generated.