Will there be a choice to opt-out? Yeah, you'll probably get a button somewhere to express that you don't want to be spied at least if you're in Europe. Will there be any auditable method for them to prove that they do respect consent? Nope, they never truly cared about consent in the first place if they make these opt-out rather than opt-in, mostly because they know that if this was opt-in most people wouldn't use it as it doesn't benefit them.

The problem is that this software is proprietary, the phones are proprietary and they give far more control to Google, Apple, Samsung and manufacturers than users, that's exactly why we have the privacy and security nightmare we have today with smartphones, and they're trying the same moves on computers as well, albeit with less success.

Where could I research this matter further?

See every single top-notch/latest flagship smartphone being announced from any major brand: Samsung, Google and Apple are all selling local AI assistant as a feature on these upcoming phones.