> after you poured 2 hours

and at the end it turns out to be 5-10 hours. Companies say "you should be able to finish it in 1-2 hours", but it's almost never true.

I think alternative is to have 1 hour coding session on a good problem. Most problems are complicated, but there could be something else. I was once asked by Uber to implement timer in JavaScript that will update DOM, also create APIs to stop/start/pause. This kind of a challenge doesn't involve any algorithm, but it shows your ability to code.

It should be enough to bring you onsite.

But I open source should work. If you contributed to Linux Kernel and it was accepted - onsite no questions asked. If you have github repo of 1000+ stars - onsite no questions asked. If you have already passed Google tech screen and was invited onsite - invite onsite no questions asked.