And since it doesn't specify what exactly will be used, I'm going to assume that *everything* will go into the training: Voice, BGM, VFX, SFX, fonts, editing styles, etc.

YouTube/Google are not in control if the companies choose to misuse your content in any way.

So, it looks like you'll be able to manually choose which company is allowed permission to use your content for Generative AI training, provided that all permission is given by the rightful owners. All of which can be changed at any time by the content owners.