I think the problem is that Google Search doesn't have to pay Android $18 billion/year to make it the default option there.
So yes, phone manufacturers have a choice here, they don't have to make Google the default.
I wouldn't recommend it for privacy, but them giving me the choice means manufacturers can do this if they want.
I agree Xiaomi loves their data collection to the point of selling pole fan that require an app to operate - I saw that one in one of their stores.
So what else is there?