Until you can do that, offering 'stop buying' as a solution is a waste of time.
"Realistic" is determined entirely by the values of the overarching system. The fate of the people at the long tail of the supply lines isn't valued. That's the single, solitary reason that this shit is still happening. Change that, and the system will adapt. The mines will get better, or they will be replaced with other mines that do it properly.
Stop settling for what your corporate overlords tell you is doable. We can do anything as a species if we choose to, good or bad. Our history shows it. Industry has every reason to tell you it's impossible because they don't want to spend the money to insure supply lines are ethically handled.
If we can mine coal in the United States without children and with relative safety, they can mine Cobalt in the same damn way. Cobalt doesn't by virtue of being cobalt need to be pried from the Earth by children.
oh you didn't know? The blood of the children is what christens the cobalt such that it works in computers...
/sarcasm
So because we can't fix their situation for them, we're allowed to actively make it worse? This is such a nonsense point of view. Exploitative industry is not like regular industry. This is not a rising tide that lifts all boats, this is enriching one or two psychopathic monsters at the expense of their entire region, and possibly financing even more in other regions.
The West does not need to go in and "fix" every developing nation, but at the same time, saying "well if we didn't sell them scrapheap ships or buy the minerals their children mine, they'd starve" is a complete abdication of responsibility for the role the demand for those minerals plays in their situation. They mine them because they can sell them, that's the whole point. If you remove the entities buying them, then there's no reason to mine them.