I really liked the take home. It is just that if you have someone doing this, you are having that person commit hours of their time to interviewing without the same investment on your end. So if you do not have the means or time to process these submissions then it is not fair to have someone spend their time on it.

I think your hiring process is great otherwise. And yes if someone isn't very familiar with every intersection of stacks there it will take them more time. That is fine too. It shows the person can learn on the spot.