I think we would have to start with the basics- what is this programme supposed to accomplish?
All of the above that you mentioned.
1- increase birth rate - will boom shortly with all those millions of ukranian women having arrived.
2- reduce poverty - history making changes
3- income top up for parents - helps middle class parents do more like sending their kids to kindergarten
4- increase consumer spending and thus help small business and economy.
5. After Poland being fu**ed over since the 89, by the introduction of neoliberalism, it's a show of political respect by the government to the demos, that Poland can dream of being a civilised western state with the social spending that this includes.
Means testing: it should be set at a level that only excludes the top 10-20 percent, then the points of benefits stopping people getting pay rises and people kombinowac to receive benefits are moot, as are the stigmatisation issues. It would nullify the political argument that the money is being wasted on the rich.