The usual problem with the unemployed humans is where the money to support them comes from

Yes, but that's only a problem in that you have to tax rich people to get their money to distribute it. My first reply was therefore "the government will tax the rich to feed the poor, what else could they do?".

But after a bit of thought, I realised that if the government owns self replicating slave robots and land, then it can use the slaves to create food without needing to tax anyone. The robots can't be taxed because their earnings go to their owners, but in this case they aren't earning anything because they give the food away. Their efforts don't take any human input so nobody needs a salary, and they can do what people can do so they can run farms and distribute food.

So, without comment on the morality of slaving human-equivalent robots (whether the robots care isn't discussed in the link), feeding unemployed people is a non-problem - the self running Roboslave farms are free food fountains.

They are borderline cornucopia machines limited to whatever humans can make and the right resources being available - in this case sunlight, land and seeds.